JP2007330650A - Dishwasher - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dishwasher which causes no air trapping in a washing pump even if the quantity of washing water is small and can wash dishes by a high washing performance. <P>SOLUTION: The dishwasher has the washing pump 13 which absorbs and pressurizes washing water supplied to a washing tub 7, a washing nozzle 14 arranged in the washing tub 7 and rotating while jetting water in response to pressurization from the washing pump 13 and washing dishes in the washing tub 7, and a control means which rotates the washing pump 13 at high speed and then switches it to low speed, varies the quantity of washing water jet from the washing nozzle 14 by repeating the process, and switches it to low speed before the quantity of water used during the high speed rotation exceeds a prescribed quantity. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a dishwasher for automatically washing dishes such as dishes and cooking utensils for home use or business use.

  As a conventional tableware washing machine, there is one that jets washing water intermittently from a nozzle. The wash water sprayed intermittently becomes an impact force when it hits the tableware, and makes it possible to easily remove the dirt adhering to the tableware. (For example, refer to Patent Document 1).

JP 2002-17646 A (first page, FIG. 1)

  The conventional dishwasher sprays wash water intermittently from the nozzle, so the wash water exerts a greater impact force on the dirt adhering to the tableware compared to the case where the wash water is sprayed uniformly. Although it improves the power, the amount of cleaning water sprayed from the nozzle is large. For this reason, a large amount of cleaning water must be prepared so that the cleaning pump does not clog the air, and running costs such as water bills There was a problem that the cost would be excessive. Further, when the cleaning pump sometimes causes air biting, there is a problem that the cleaning power is reduced, noise is increased, and durability is reduced.

  The present invention has been made to solve the above-described problems, and provides a dishwasher that can clean dishes with a high cleaning power without having an air bit in a cleaning pump even when the amount of cleaning water is small. For the purpose.

  A dishwasher according to the present invention includes a washing tank for storing dishes, a washing pump for sucking and pressurizing washing water supplied into the washing tank, and a washing pump disposed in the washing tank. Washing water sprayed from the washing nozzle by rotating while jetting water according to pressure and washing the dishes in the washing tank, and alternately switching the washing pump between high speed rotation and low speed rotation. And a control means for switching to low-speed rotation before the amount of water used during high-speed rotation exceeds a predetermined amount.

  In the present invention, the cleaning pump is alternately switched between high-speed rotation and low-speed rotation to change the amount of cleaning water sprayed from the cleaning nozzle before the amount of water used during high-speed rotation exceeds a predetermined amount. Thus, the tableware can be washed with high washing power while saving washing water without causing the washing pump to chew air.

Embodiment 1 FIG.
FIG. 1 is a schematic configuration diagram showing a dishwasher according to Embodiment 1 of the present invention, FIG. 2 is an explanatory diagram of the amount of water used for washing at high speed rotation and low speed rotation, and FIG. FIG. 4 is a diagram showing the correlation of the amount of water used for cleaning, and FIG. 4 is a diagram showing changes in the number of rotations of the cleaning pump.
The tank 2 provided in the dishwasher main body 1 has a water inlet 3 and a water outlet 6 for drawing water from the outside, respectively, and a water level sensor 5 for detecting the water level of the water 4 supplied through the water inlet 3. And a heater 6 for heating the stored water 4 are disposed. The water level sensor 5 is for detecting the amount of water required in each of the cleaning process and the rinsing process. The washing tank 7 provided above the tank 2 is provided with a lower basket 8 and an upper basket 9 for detaching the tableware to be washed, and the washing water supplied into the washing tank 7 on the side surface ( A reflective liquid level sensor 10 for detecting a change in the liquid level of the rinse water is attached. A hot water supply pump 11 is installed on a pipe line provided with a hot water supply port 12 in the washing tank 7. The hot water supply pump 11 is driven and controlled by the control unit 20 in each of the cleaning process and the rinsing process, and the heater 20 is configured so that the water 4 in the tank 2 becomes, for example, 60 ° C. by the energization control of the control unit 20. Heat to. The energization control to the heater 2 is performed until rinsing is completed.

  The cleaning pump 13 includes a casing portion 13 a (with built-in blades) and a motor 13 b. The cleaning pump 13 sucks and pressurizes cleaning water (rinsing water) supplied into the cleaning tank 7 and discharges it to the cleaning nozzle 14. This cleaning nozzle 14 is rotatably attached to the casing 13a side of the cleaning pump 13, and in one direction while injecting cleaning water (rinse water) from a plurality of injection ports 14a according to the amount of water from the cleaning pump 13. Rotate. This rotation is caused by the reaction force of the washing water jetting force jetted from the plurality of jetting ports 14a. A drainage pump 15 for draining sewage in the cleaning tank 7 from the drain port 16 is installed on the bottom side of the cleaning tank 7. A filter 17 is detachably attached to an upstream side of a pipe line connecting the cleaning tank 7 and the cleaning pump 13. The filter 17 collects leftovers that have fallen from the tableware during washing. The drain pump 15 is driven and controlled by the control unit 20 every time cleaning and rinsing of the tableware is completed, and the above-described cleaning pump 13 is driven and controlled by the control unit 20 in each of the cleaning process and the rinsing process.

  Here, drive control of the cleaning pump 13 by the control unit 20 will be described. First, the relationship between the rotation speed of the cleaning pump 13 and the amount of water used for cleaning (rinsing) will be described with reference to FIG. When the cleaning pump 13 is rotated at a high rotational speed A1, the amount of water used for cleaning (rinsing), that is, the cleaning water sprayed from the cleaning nozzle 14 (rinsing water) is not collected at the bottom of the cleaning tank 7. When the amount of water (amount of water used) increases with time and approaches the first amount of water used L1, and when switching from this state to the low speed rotation speed A2, the amount of water used decreases gradually and approaches the second amount of water used L2. To go. Thus, the amount of water used increases during high-speed rotation and decreases during low-speed rotation. The first used water amount L1 is the upper limit value of the used water amount at the time of high speed rotation, and the second used water amount L2 is the upper limit value of the used water amount at the time of low speed rotation, and these were obtained by measuring in advance. The amount of water used.

  In the first embodiment, the amount of water used for the cleaning water (rinse water) when the cleaning pump 13 rotates at high speed (the amount of water not recovered at the bottom of the cleaning tank 7) is reduced. For example, as shown in FIG. 3, when the amount of water used when the cleaning pump 13 is rotated at the high speed A1 reaches a predetermined amount L that is smaller than the first amount of water L1 (upper limit amount of water used), the cleaning pump 13 Is switched from the high speed A1 to the low speed A2. When the amount of water used at the time of low-speed rotation decreases from a predetermined amount L to, for example, a certain amount, it is switched again to the high-speed rotation number A1, and this is repeated. In this case, as shown in FIG. 4, the rotation speed of the cleaning pump 13 changes in a pulse shape. The determination as to whether or not the amount of water used has reached a predetermined amount L and the determination as to whether or not the amount of water used has decreased from the predetermined amount L to a certain amount are made according to the reflective liquid level sensor 10 provided in the cleaning tank 7. This is based on the liquid level detection.

Next, the operation of the dishwasher configured as described above will be described with reference to FIGS.
When the water level sensor 5 installed in the tank 2 detects the water 4, the control unit 20 determines that the water 4 has been supplied up to the height of the water level sensor 5, and notifies, for example, by sound that the water supply is stopped and washed. Enter the process. First, the heater 5 is energized to heat the water 4 in the tank 2, and when the water temperature rises to, for example, 60 ° C., the hot water supply pump 11 is driven to supply the hot water 4 in the tank 2 into the washing tank 7. . At this time, it is determined through the reflective liquid level sensor 10 whether or not a predetermined total amount of water necessary for cleaning is supplied, and the heater 5 is energized so that the water temperature of the tank 2 is maintained at 60 ° C. To control. In addition, the energization control to the heater 5 is performed until rinsing is completed as described above.

  When the control unit 20 detects that the total amount of water necessary for cleaning is supplied into the cleaning tank 7 through the reflective liquid level sensor 10, the control unit 20 stops driving the hot water supply pump 11, and then rotates the cleaning pump 13 at high speed. The cleaning water is jetted from the cleaning nozzle 14 by rotating at a number A1. At this time, it is determined based on the liquid level detection of the reflective liquid level sensor 10 whether or not the amount of water used that has not been collected at the bottom of the cleaning tank 7 has reached a predetermined amount L. As shown in FIG. 3, when the amount of water used reaches a predetermined amount L, the rotation speed of the cleaning pump 13 is switched from the high-speed rotation speed A1 to the low-speed rotation speed A2, and the cleaning nozzle has less cleaning water than the injection amount during high-speed rotation. 14 is injected. At this time, it is determined whether or not the amount of water used has decreased from the predetermined amount L to a certain amount based on the liquid level detection of the reflective liquid level sensor 10, and the amount of water used has decreased to a certain amount as shown in FIG. At that time, the rotational speed of the cleaning pump 13 is switched again to the high speed rotational speed A1, and the above-described operation is repeated. In this case, as described above, the rotation speed of the cleaning pump 13 changes in a pulse manner (see FIG. 4).

  On the other hand, when the cleaning pump 13 rotates at the high speed rotation number A1, the cleaning nozzle 14 rotates while applying cleaning water to the tableware of the upper basket 9, and when the cleaning pump 13 rotates at the low speed rotation number A2. Rotates while applying washing water to the tableware in the lower basket 8. In this case, when the cleaning pump 13 rotates with the high speed rotation speed A1 and the low speed rotation speed A2 as one cycle, since the cleaning nozzle 14 does not rotate once, the injection timing of the cleaning water injected from the cleaning nozzle 14 shifts.

  When the cleaning time of the dishes has elapsed, the driving of the cleaning pump 13 is stopped, and then the drainage pump 15 is driven to drain the sewage in the cleaning tank 7 from the drainage port 16 to the outside, and the cleaning process is completed. Thereafter, the hot water supply pump 11 is driven again and the rinsing process is started. Note that the drive control of the hot water supply pump 11, the drive control of the cleaning pump 13, and the drive control of the drainage pump 15 in the rinsing process are substantially the same as in the above-described cleaning process, and thus the description of the operation is omitted.

  As described above, according to the first embodiment, in each of the cleaning process and the rinsing process, the cleaning pump 13 is rotated at the high speed rotation number A1, and the amount of water used for the cleaning water (rinsing water) at this time is the first. When the predetermined amount L smaller than the used water amount L1 is reached, the rotation speed of the cleaning pump 13 is switched from the high speed rotation number A1 to the low speed rotation number A2, and the use amount of the cleaning water (rinse water) at the low speed rotation is changed from the predetermined amount L. When it decreased to a certain amount, the rotation speed of the cleaning pump 13 was switched from the low-speed rotation speed A2 to the high-speed rotation speed A1, and this was repeated, so the tableware was made high while saving washing water (rinsing water). It can be washed with detergency.

  In the first embodiment, when the amount of water used at the time of high speed rotation of the cleaning pump 13 reaches the predetermined amount L, the rotation speed is switched from the high speed rotation speed A1 to the low speed rotation speed A2, and used at the low speed rotation. When the amount of water decreased from the predetermined amount L to a certain amount, the rotational speed was switched from the low speed rotational speed A2 to the high speed rotational speed A1, but the amount of water used during the high speed rotation of the cleaning pump 13 reached the predetermined amount L. Time is measured in advance, and the time when the amount of water used during low-speed rotation is reduced from a predetermined amount L to a predetermined amount is measured in advance, and the rotational speed A1 of the cleaning pump 13 is based on these times. , A2 may be switched.

  For example, as shown in FIG. 5, when the time T1 has elapsed since the cleaning pump 13 is rotated at the high speed rotation number A1 and the high speed rotation is started, it is determined that the amount of water used during the high speed rotation has reached a predetermined amount L. Then, when the rotational speed is switched to the low speed rotational speed A2 and the time T2 has elapsed since the switching to the low speed rotational speed, it is determined that the amount of water used at the low speed rotational speed has decreased from the predetermined amount L to a constant amount, and the high speed is again reached. It switches to rotation speed A1, and repeats it by making time T1 and T2 into one period. Note that the time T1 during high-speed rotation is shorter than the time T2 during low-speed rotation. In this case as well, the tableware can be washed with high detergency while saving washing water (rinse water).

  In the first embodiment, the cleaning pump 13 is rotated at the high speed rotation speed A1, and then the rotation speed is switched to the low speed rotation speed A2, and this is repeated. First, the cleaning pump is rotated at the low speed rotation speed A2. 13 may be rotated, and then the rotational speed may be switched from the low speed rotational speed A2 to the high speed rotational speed A1, and this may be repeated.

Embodiment 2. FIG.
In the first embodiment, the first used water amount L1 that is the upper limit of the used water amount at the time of high speed rotation of the cleaning pump 13, the second used water amount L2 that is the upper limit of the used water amount at the time of low speed rotation, and the predetermined amount L. In the second embodiment, the first and second water usage amounts L1 and L2 are automatically calculated from the predetermined high speed and low speed, and the values measured in advance are used. The predetermined amount L is obtained based on the obtained L1 and L2, and the dishwasher of the second embodiment will be specifically described below. The second embodiment is substantially the same as the first embodiment except for the control unit 20, and will be described with reference to FIG.

The dishwasher main body 1 according to the second embodiment is provided with a switch (not shown) for selecting either standard washing or strong washing according to the degree of contamination of the dishes, for example. In the control unit 20, the rotation speeds A1 and A2 of the cleaning pump 13 are set as data corresponding to the standard cleaning, and the rotation speeds A11 and A21 are set as data corresponding to the strong cleaning. A1 and A21 are high-speed rotation speeds and have a relationship of A1 <A21. Moreover, A2 and A21 are low speed rotation speeds, and have a relationship of A2 <A21. When either standard cleaning or strong cleaning is selected, the first use water amount L1 (upper limit use water amount) and the second use water amount L2 are calculated using the following equations.
L1 = W1 / μ… (1)
L2 = W2 / μ… (2)

  W1 in the formula (1) is the amount of water sprayed from the cleaning nozzle 14 when the cleaning pump 13 is rotated at a high speed, and is the amount of water jetted at the high speed rotation speed A1 and the high speed rotation speed A11. There is a jet water amount. W2 in the formula (2) is the amount of water sprayed from the cleaning nozzle 14 when the cleaning pump 13 is rotated at a low speed, and is the amount of water jetted at the low speed A2 and the low speed A21. There is a jet water amount. These jet water amounts are previously measured by experiments and are set in the control unit 20 as data. Further, μ is a recovery rate indicating the rate at which the sprayed cleaning water is recovered at the bottom of the cleaning tank 7 per unit time, and is set in the control unit 20 as data as described above.

  Further, the control unit 20 calculates an intermediate value between the first used water amount L1 and the second used water amount L2 obtained from the above formula. This intermediate value is a predetermined amount L when the cleaning pump 13 is switched from high speed rotation to low speed rotation. A certain amount when switching from the low speed rotation A21 to the high speed rotation A11 is the same value as in the first embodiment. The first used water amount L1 obtained by the above formula is larger at A11 than at the high speed rotation number A1, and the second used water amount L2 is greater at A21 than at the low speed rotation number A2. It is increasing.

  In the second embodiment, when either standard cleaning or strong cleaning is selected with a switch, the control unit 20 enters the cleaning process and cleans the hot water (60 ° C.) 4 in the tank 2 via the hot water supply pump 11. The water is supplied into the tank 7 and calculation of the first and second water usage amounts L1 and L2 starts based on the selection of the switch. When the selection is strong cleaning, the first use water amount L1 is calculated by applying the jet water amount W1 and the recovery rate μ at the high speed rotation speed A11 to the equation (1), and then at the low speed rotation speed A21. The second water usage amount L2 is calculated by applying the jet water amount W2 and the recovery rate μ to the equation (2), and the predetermined amount L is obtained based on L1 and L2 obtained by these calculations.

  Then, the cleaning pump 13 is rotated at the high speed rotation speed A11, and when the amount of water used at this time reaches the calculated predetermined amount L, the rotation speed of the cleaning pump 13 is switched from the high speed rotation speed A11 to the low speed rotation speed A21. When the amount of water used during low-speed rotation decreases from the predetermined amount L to a constant amount, the rotation speed of the cleaning pump 13 is switched from the low-speed rotation speed A21 to the high-speed rotation speed A11, and this is repeated. In this case, the injection amount at the high speed rotation and the low speed rotation injected from the cleaning nozzle 14 is larger than that when the cleaning pump 13 is rotated at the rotation speeds A1 and A2, as described above. That is, the dishes are washed with a stronger jetting force than at the rotation speeds A1 and A2.

  The control of the cleaning pump 13 in the rinsing process is performed when the cleaning pump 13 is rotated at the high speed rotation speed A11 and the amount of water used at this time reaches the calculated predetermined amount L, as in the cleaning process described above. In addition, when the rotation speed of the cleaning pump 13 is switched from the high speed rotation speed A11 to the low speed rotation speed A21 and the amount of water used during the low speed rotation decreases from a predetermined amount L to a certain amount, the rotation speed of the cleaning pump 13 is changed to the low speed rotation speed. Switching from A21 to the high speed A11 is repeated.

  As described above, in the second embodiment, the first and second water usage amounts L1 and L2 are automatically calculated from the selected rotation speed (high speed and low speed) of the cleaning pump 13, and the obtained L1 and L2 are obtained. Since the predetermined amount L for switching the cleaning pump 13 from the high speed rotation to the low speed rotation can be calculated using this, the cleaning pump 13 can be rotated at various high speed rotations and low speed rotations. It is possible to easily wash stubborn dirt adhering to the tableware, a large amount of oil, etc., and there is an effect that the cleaning power is improved.

  In the second embodiment, the control of the cleaning pump 13 in the cleaning process and the rinsing process is the same. However, the cleaning pump and the rinsing process may be rotated at different rotational speeds.

Embodiment 3 FIG.
In the third embodiment, when the time for high-speed rotation and the time for low-speed rotation of the cleaning pump 13 have been determined in advance, the cleaning pump 13 is configured to air-engage the total amount of water required for the cleaning process and the rinsing process. The dishwasher according to the third embodiment will be described below. The third embodiment is substantially the same as the first embodiment except for the control unit 20, and will be described with reference to FIG.

In the control unit 20 in the third embodiment, a time T1 for rotating the cleaning pump 13 at the high speed A1 and a time T2 for rotating the cleaning pump 13 at the low speed A2 are set, and the total required for each of the cleaning process and the rinsing process is set. Formula (3) for calculating the amount of water S is set.
S = Xm + W1 / μ-(exp {μT2}-1) (W1-W2) / μ (exp {μ (T1 + T1)}-1)… (3)
Xm in the equation is the value of the amount of water that does not cause the air to be caught by the cleaning pump 13 when the cleaning pump 13 is rotated, and is a value obtained by experiments in advance. S is the minimum amount of water in the washing tank 7 that is necessary when the rotation is alternately switched at the high speed A1 during the time T1 and at the low speed A2 during the time T2. W1 is the amount of water sprayed from the cleaning nozzle 14 when the cleaning pump 13 is rotated at the high speed A1, and W2 is the cleaning nozzle when the cleaning pump 13 is rotated at the low speed A2. The amount of water jetted per unit time from 14 and μ is a recovery rate indicating the rate at which the jetted wash water is recovered at the bottom of the cleaning tank 7 per unit time.

Next, the operation will be described with reference to FIG. In addition, FIG. 5 is a figure which shows the change of the rotation speed of the washing pump in Embodiment 3. In FIG.
The control unit 20 calculates the minimum total amount of water S to be supplied to the cleaning tank 7 by using the above formula every time the cleaning process and the rinsing process are entered. Then, the hot water supply pump 11 is driven to determine whether or not the total water amount S has been reached based on the liquid level detection of the reflective liquid level sensor 10. When the cleaning water in the cleaning tank 7 reaches the total water amount S, the hot water supply pump 11 is stopped and the cleaning pump 13 is driven. As shown in FIG. 5, during the time T1, the rotation is performed at the high speed A1, and then during the time T2, the rotation is performed at the low speed A2.

  As described above, according to the third embodiment, when the time T1 at the time of high speed rotation and the time T2 at the time of low speed rotation are given, the minimum required water amount (total water amount) in which the air is not caught in the cleaning pump 13 is given. Since the dishes can be washed or rinsed in S), there is a water saving effect.

Embodiment 4 FIG.
In the first to third embodiments, the first used water amount L1 that is the upper limit of the used water amount at the time of high speed rotation of the cleaning pump 13 and the second used water amount L2 that is the upper limit of the used water amount at the time of low speed rotation are the cleaning pump 13. However, according to the amount of water collected at the bottom of the washing tub 7 according to the type and number of tableware placed in the lower basket 8 and the upper basket 9, The first and second water usage amounts L1, L2 and the predetermined amount L are changed. This function is executed as a preliminary cleaning before the cleaning step, and the dishwasher of the fourth embodiment will be described below. The fourth embodiment is substantially the same as the first embodiment except for the control unit 20, and will be described with reference to FIG.

  For example, when the controller 20 in the fourth embodiment detects an on-operation of a switch for promoting preliminary washing after detecting an on-operation of a dishwashing start switch (not shown), the first and second uses The operation for obtaining the water amounts L1, L2 and the predetermined amount L is started. When the water 4 is supplied into the tank 2, the hot water supply pump 11 is driven to supply the water 4 in the tank 2 to the cleaning tank 7, and the liquid level detection of the reflective liquid level sensor 10 is performed to detect the inside of the cleaning tank 7. It is determined whether or not the amount of water 4 has reached the amount of water necessary for preliminary cleaning. When the amount of water necessary for the preliminary cleaning is reached, the hot water supply pump 11 is stopped, and then the cleaning pump 13 is rotated at the high speed A1. At this time, when the water level in the cleaning tank 7 (washing water), which is lowered by being jetted from the washing nozzle 14, is detected through the reflective liquid level sensor 10, and this water level drop is in a steady state, the water level at that time The water level difference is obtained by subtracting the water level from before the cleaning pump 13 is driven, and the unrecovered amount of water is calculated from the product of the water level difference and the preset sectional area A of the cleaning tank 7, Is the first used water amount L1 (upper limit used water amount).

  Next, the cleaning pump 13 is switched from the high speed rotation speed A1 to the low speed rotation speed A2, and the lowering of the water level in the cleaning tank 7 is detected through the reflective liquid level sensor 10 in the same manner as described above. When this happens, the water level at that time is subtracted from the water level before driving the cleaning pump 13 to obtain the water level difference, and the amount of water not recovered from the product of the water level difference and the cross-sectional area A of the cleaning tank 7 is calculated. It calculates and makes this 2nd use water amount L2. Further, an intermediate value is calculated from the obtained first and second water usage amounts L1 and L2, and this is set as a predetermined amount L. A certain amount when switching from the low speed rotation A21 to the high speed rotation A11 is the same value as in the first embodiment.

  When the calculation of the first and second used water amounts L1 and L2 and the predetermined amount L according to the type and number of tableware placed on the lower basket 8 and the upper basket 9 is completed, the drain pump 15 is driven and the washing tank The waste water in 7 is drained and the cleaning process is started. The switching from the high speed rotation to the low speed rotation of the cleaning pump 13 in the cleaning process is performed when the amount of water used at the time of high speed rotation reaches the predetermined amount L calculated in the preliminary cleaning, as in the first embodiment. The rotation speed changes in a pulse manner. The cleaning pump 13 in the rinsing process is controlled in the same manner as in the cleaning process.

  As described above, according to the fourth embodiment, before entering the cleaning process, the cleaning pump 13 is changed from a high speed rotation to a low speed rotation according to the type and number of tableware placed on the lower basket 8 and the upper basket 9. Since the predetermined amount L for switching is determined, there is an effect that the cleaning pump 13 can clean (rinse) the table without causing air biting.

Embodiment 5 FIG.
In the fourth embodiment, the first and second water usage amounts L1 and L2 are determined according to the type and number of tableware installed in the lower basket 8 and the upper basket 9, and the washing pump 13 is based on the L1 and L2. The predetermined amount L for switching from high-speed rotation to low-speed rotation is obtained, but the fifth embodiment obtains the washing water recovery rate μ after installing the tableware, and this recovery rate μ is set to the second embodiment. The first and second water usage amounts L1 and L2 are determined by applying the formulas (1) and (2) shown, and the predetermined amount L is obtained based on these L1 and L2. The dishwasher of form 5 will be described. The fifth embodiment is substantially the same as the first embodiment except for the control unit 20, and will be described with reference to FIG.

In the fifth embodiment, the above-described arithmetic processing is performed by the control unit 20 and is performed at the time of preliminary cleaning before entering the cleaning process. For example, when the amount of water necessary for preliminary cleaning is stored in the cleaning tank 7, the cleaning pump 13 is driven for a while to stop. Then, through the liquid level detection of the reflective liquid level sensor 10, the amount of water ΔX collected at the bottom of the washing tank 7 during a preset time Δt is calculated, and the water level at that time is measured through the reflective liquid level sensor 10. To do. As shown in FIG. 6, when the water level at that time is y, the amount X of the cleaning water remaining at the bottom of the cleaning tank 7 is calculated from the preset cross-sectional area A of the cleaning tank 7. Then, the recovery rate μ is calculated by applying each value to the following formula. S in the formula is the total amount of water supplied into the cleaning tank 7 during the preliminary cleaning.
μ = ΔX / (S-X) Δt… (4)

  The recovery rate μ obtained as described above is applied to the same formulas (1) and (2) as those in the second embodiment, and the first and second water usage amounts L1 and L2 are calculated. An intermediate value of the obtained first and second water usage amounts L1 and L2 is calculated, and this is set as a predetermined amount L for switching the washing pump 13 from high speed rotation to low speed rotation. In the fifth embodiment, W1 in the equation (1) is the amount of water jetted per unit time that is jetted from the washing nozzle 14 when the washing pump 13 is rotated at the high speed A1, and W2 Is the amount of jetted water per unit time that is jetted from the washing nozzle 14 when the washing pump 13 is rotated at the low speed A2.

  Thereafter, the drainage pump 15 is driven to drain the sewage in the cleaning tank 7 and the cleaning process is started. The switching from the high speed rotation to the low speed rotation of the cleaning pump 13 in the cleaning process is performed when the amount of water used at the high speed rotation reaches the predetermined amount L calculated at the time of preliminary cleaning, as in the first embodiment. The number of rotations changes in a pulse manner (see FIG. 4). In the rinsing process, the cleaning pump 13 is controlled as in the cleaning process.

  As described above, according to the fifth embodiment, the recovery rate of the cleaning water is obtained during the preliminary cleaning before entering the cleaning process, and the predetermined amount L for switching the cleaning pump 13 from the high speed rotation to the low speed rotation based on this result. Therefore, even if various types of tableware or different types of tableware are installed, a dishwasher having a water-saving effect can be provided without causing the cleaning pump to chew air.

In the fifth embodiment, the recovery rate μ is obtained using the equation (4), but instead, the recovery rate μ may be obtained from the following equation (5). .
μ = W / (S-X) (5)
W in the formula rotates the cleaning pump 13 at a predetermined rotational speed until it reaches a steady state. At this time, the amount of water sprayed from the cleaning nozzle 14 is injected into the cleaning tank 7 during preliminary cleaning. The total amount of water supplied, X, is the amount of cleaning water stored in the cleaning tank 7 in the steady state. In this case, since the predetermined amount L for switching the washing pump 13 from the high speed rotation to the low speed rotation can be determined based on the recovery rate obtained from this equation, various types of tableware and different types of tableware are installed as described above. Even if this is done, a dishwasher with a water-saving effect can be provided without causing the cleaning pump to chew air.

  In addition, the first and second water usage amounts L1 and L2 are calculated from the recovery rates μ obtained by the equations (4) and (5). The recovery rates μ are described in the third embodiment. By applying the equation (3), the total water amount S required in each step for the washing step and the rinsing step may be obtained.

  By the way, in each embodiment mentioned above, as a structure of the dishwasher, although wash water was once stored in the tank 2 and heated, it demonstrated as a structure which supplies hot water to the washing tank 7, However, it is not restricted to this. It is apparent that the present invention can also be applied to a dishwasher in which water is poured directly into the washing tank 7 and washed while boiling with the heater 6 installed in the washing tank 7. Moreover, the reflective liquid level sensor 10 can be replaced with a sensor such as an electric field sensor that can detect the water level.

It is a schematic block diagram which shows the dishwasher which concerns on Embodiment 1 of this invention. It is explanatory drawing of the amount of water used for washing | cleaning at the time of high speed rotation and low speed rotation. It is a figure which shows the correlation of the rotation speed of a washing pump, and the amount of water used for washing | cleaning. It is a figure which shows the change of the rotation speed of a washing pump. It is a figure which shows the change of the rotation speed of the washing pump in Embodiment 3. FIG. It is a figure which shows the relationship between the amount of washing water stored in the washing tank, and the water level.

Explanation of symbols

1 dishwasher body, 2 tanks, 5 water level sensor, 6 heater, 7 washing tank, 8 lower basket, 9 upper basket, 10 reflective liquid level sensor, 11 hot water pump, 13 washing pump,
13a casing part, 13b motor, 14 cleaning nozzle, 14a injection port, 15 drainage pump.

Claims (7)

A washing tank for storing tableware,
A cleaning pump for sucking and pressurizing the cleaning water supplied into the cleaning tank;
A cleaning nozzle that is disposed in the cleaning tank, rotates while spraying water in response to pressure from the cleaning pump, and cleans dishes in the cleaning tank;
The cleaning pump is alternately and repeatedly switched between high speed rotation and low speed rotation to change the amount of cleaning water sprayed from the cleaning nozzle, and before the amount of water used during high speed rotation exceeds a predetermined amount, the speed is decreased to low speed rotation. A dishwasher comprising a control means for switching. A liquid level sensor for detecting the level of the cleaning water in the cleaning tank;
2. The dishwasher according to claim 1, wherein the control means determines whether or not the amount of water used during high-speed rotation exceeds the predetermined amount through the liquid level sensor.   2. The dishwashing according to claim 1, wherein the control means is based on a time within a range in which the amount of water used during high-speed rotation does not exceed the predetermined amount when switching from high-speed rotation to low-speed rotation. Machine.   The control means calculates and calculates an upper limit use amount of water used when rotating the high-speed rotation based on a jet water amount when the cleaning pump is rotated at a high speed and a recovery rate of the cleaning water obtained in advance. 3. The dishwasher according to claim 1, wherein the predetermined amount smaller than the upper limit water usage is calculated and used as a switching timing from a high speed rotation to a low speed rotation of the washing pump.   The control means is set in advance for each time of high speed rotation and low speed rotation of the cleaning pump, and is necessary for each of the cleaning process and the rinsing process based on each time and the recovery rate of the cleaning water obtained in advance. 4. The dishwasher according to claim 1, wherein a total amount of water is calculated, and the total amount of water is supplied into the washing tank.   The control means rotates the washing pump at a high speed before entering the washing step, measures the lowered water level in the washing tank from before the washing pump is rotated through the liquid level sensor, and the lowered water level. Based on the above, the upper limit amount of water used during high speed rotation is calculated, then the predetermined amount less than the calculated upper limit water consumption is calculated, and this is switched from the high speed rotation of the washing pump to the low speed rotation. 3. The dishwasher according to claim 2, wherein timing is set. The control means rotates the cleaning pump before jetting into the cleaning process to inject cleaning water from the cleaning nozzle, and based on the remaining amount of water in the cleaning tank when the cleaning pump is stopped 6. The dishwasher according to claim 4 or 5, wherein the recovery rate of the dish is calculated.

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