Treatment agent supply device and dishwasher

Abstract

To enable prevention of such a problem that a part of a predetermined amount of a treatment agent pumped to the downstream side portion 42b of a main flow passage 42 upon pumping operation remains in the main flow passage, in a treatment agent supply device in which: switching means 44 is disposed at a confluence portion between the main flow passage 42 for supplying water to a supplying target portion 2 and a sub flow passage 43 communicating with a treatment agent storage tank 40; a pumping unit 45 composed of a positive displacement pump 451, an upstream side check valve 452, and a downstream side check valve 453 is intervene; and a bypass path 46 in parallel with the switching means 44 and the pumping unit 45 is provided.SOLUTION: Restriction means 461 is intervened in a bypass path 46, so that a ratio of an amount of water supplied to a supplying target portion 2 through a main flow passage 42, to predetermined amount of water supplied to the supplying target portion 2 through the main flow passage 42 and the bypass path 46 upon delivering operation becomes equal to or more than a value necessary to supply all of a predetermined amount of treatment agent to the supplying target portion 2.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a treatment agent supplying device capable of sucking up a predetermined amount of a treatment agent such as a detergent from a storage tank of the treatment agent and supplying it to a supply portion together with water, and to a dishwasher equipped with this treatment agent supplying device. [Background technology]

[0002] Conventionally, as a treatment agent supplying device of this kind, there is known a device that includes a main passage with a water supply valve at its upstream end that supplies water to a supply portion, and a side flow passage that introduces a treatment agent stored in a storage tank into the main passage, and a suction unit is interposed in the side flow passage, the suction unit being composed of a positive displacement pump, a first check valve on the upstream side that allows only a flow to be sucked into the pump, and a second check valve on the downstream side that allows only a flow to be pushed out from the pump, and by opening the water supply valve and driving the pump, a predetermined amount of treatment agent is sucked out from the storage tank and sent out to the main passage, and this treatment agent is supplied to the supply portion together with water through the main passage (for example, see Patent Document 1). However, in this device, the treatment agent in the pump or the check valve cannot be washed away with water, and the treatment agent remaining in the pump or the check valve may harden, causing the suction unit to malfunction.

[0003] Accordingly, conventionally, there have been considered a first type of treatment agent supplying device in which a switching means is disposed at the junction of the main passage and the secondary passage, a suction unit is interposed in a part of the main passage downstream of the switching means, and a bypass path is provided connecting the part of the main passage upstream of the switching means with the part of the main passage downstream of the suction unit; and a second type of treatment agent supplying device in which a suction unit is interposed in a bypass path provided to connect the part of the main passage upstream of the switching means disposed at the junction of the main passage and the secondary passage with the part of the main passage downstream of the switching means.

[0004] In the first type of treatment agent supplying device, the switching means is switchable between a first state in which the switching means blocks communication between a portion of the main passage upstream of the switching means and a portion of the main passage downstream of the switching means and connects the by-flow passage with the portion of the main passage downstream of the switching means, and a second state in which the switching means blocks communication between the portion of the main passage upstream of the switching means and a portion of the main passage downstream of the switching means and connects the portion of the main passage downstream of the switching means and connects the by-flow passage with the portion of the main passage downstream of the switching means. The control means of the treatment agent supplying device is configured to perform a suction operation in which the water supply valve is closed and the switching means is switched to the first state to drive the pump to suction a predetermined amount of treatment agent from the storage tank toward the portion of the main passage downstream of the switching means, and a delivery operation in which the water supply valve is opened and the switching means is switched to the second state to deliver the predetermined amount of treatment agent suctioned in the suction operation to a supply portion together with water via the main passage. With this system, during discharge operation, the treatment agent inside the pump and the check valve is washed away by water passing through the main passage, preventing malfunction of the suction unit due to treatment agent remaining inside the pump or the check valve.

[0005] In the second type of treatment agent supplying device, the switching means can be switched between a first state in which the communication between the part of the main passage upstream of the switching means and the part of the main passage downstream of the switching means is blocked and the by-flow passage is connected to the part of the main passage upstream of the switching means, and a second state in which the communication between the part of the main passage upstream of the switching means and the part of the main passage downstream of the switching means is connected and the communication between the by-flow passage and the part of the main passage upstream of the switching means is blocked. The control means of the treatment agent supplying device is configured to perform a suction operation in which the water supply valve is closed and the switching means is switched to the first state, and the pump is driven to suction a predetermined amount of treatment agent from the storage tank toward the part of the main passage upstream of the switching means, and a delivery operation in which the water supply valve is opened and the switching means is switched to the second state, and the predetermined amount of treatment agent sucked out in the suction operation is delivered to the supply part together with water through the main passage. In this device, by making the volume of the part of the main passage upstream of the switching means equal to or greater than the predetermined amount, the treatment agent does not reach the suction unit during the suction operation. Therefore, the treatment agent does not enter the pump or the check valve, and malfunction of the suction unit caused by the treatment agent remaining in the pump or the check valve can be prevented. Even if the treatment agent reaches the suction unit during suction operation, the treatment agent in the pump and the check valve is washed away by water passing through the bypass during delivery operation, so malfunction of the suction unit can be prevented.

[0006] However, in both the first and second types of treatment agent supplying devices, water is likely to flow into the bypass passage during discharge operation, and even if the amount of water supplied through the main passage and the bypass passage during discharge operation reaches a predetermined specified water amount, the amount of water flowing through the main passage is insufficient, and some of the specified amount of treatment agent sucked out during suction operation may remain in the main passage. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2020-74823 A Summary of the Invention [Problem to be solved by the invention]

[0008] In view of the above, the present invention has as its first object to provide a treatment agent supplying device of the above-mentioned first or second type that is capable of preventing a portion of a predetermined amount of treatment agent sucked out during suction operation from remaining in the main passage during discharge operation, and has as its second object to provide a dishwasher equipped with this treatment agent supplying device. [Means for solving the problem]

[0009] In order to solve the first problem, the first invention of the present application is characterized in that, in the first or second type of treatment agent supplying device, a throttling means is provided in the bypass passage for throttling the flow rate of water flowing through the bypass passage, so that the proportion of the amount of water supplied to the supplying part via the mainstream passage out of a predetermined specified amount of water supplied to the supplying part via the mainstream passage and the bypass passage during delivery operation is equal to or greater than the value required to deliver all of the predetermined amount of treatment agent.

[0010] Furthermore, in order to solve the first problem, the second invention of the present application provides a treatment agent supplying device of the first type, further comprising second switching means which is switchable between an open state, which allows water to pass through the bypass path, and a blocked state, which prevents water from passing through the bypass path, in either the bypass path, the branch point between the bypass path and a part of the main passage upstream of the switching means, or the junction of the bypass path and a part of the main passage downstream of the suction unit, and the control means switches the second switching means to the open state during operation to supply only water to the supply part, but switches the second switching means to the blocked state at least during discharge operation.

[0011] In addition, in order to solve the second problem described above, the third invention of the present application is a dishwasher equipped with a washing tub for storing tableware, and is equipped with a treatment agent supplying device capable of supplying a predetermined amount of detergent sucked out from a storage tank of the detergent as a treatment agent together with water to the washing tub as a supply receiving part, characterized in that the treatment agent supplying device is configured as the treatment agent supplying device of the first or second invention described above.

[0012] According to the first aspect of the invention, the throttle means disposed in the bypass passage increases the flow rate of water flowing through the main passage, and when a specified amount of water is supplied to the supply portion through the main passage and the bypass passage in the delivery operation, the specified amount of treatment agent sucked into the main passage during the suction operation can be entirely delivered from the main passage. According to the second aspect of the invention, the second switching means is switched to a blocking state in the delivery operation, and water does not flow through the bypass passage, so that the specified amount of water supplied to the supply portion flows only through the main passage, and the specified amount of treatment agent sucked into the main passage during the suction operation can be entirely delivered from the main passage. Therefore, it is possible to prevent a portion of the specified amount of treatment agent sucked out during the suction operation from remaining in the main passage during the delivery operation. [Brief description of the drawings]

[0013] [Figure 1] 1 is a schematic cross-sectional side view of a dishwasher equipped with a treatment agent supplying device according to an embodiment of the present invention. [Diagram 2] 1 is a circuit diagram of a treatment agent supplying device according to a first embodiment of the present invention. [Diagram 3] FIG. 5 is a circuit diagram of a treatment agent supplying device according to a second embodiment of the present invention. [Figure 4] FIG. 5 is a circuit diagram of a treatment agent supplying device according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The dishwasher shown in Fig. 1 comprises an exterior case 1, and a washing tub 2 for storing tableware W, which is provided inside the exterior case 1 at the front so as to be freely inserted and removed, and water is supplied into the washing tub 2 via a water supply passage 3 and a treatment agent supplying device 4, which will be described in detail later. A dishwashing basket 21 for placing the tableware W therein, a washing nozzle 22 for spraying washing water toward the dishwashing basket 21, and a heater 23 are provided inside the washing tub 2. A stop valve 31 is provided in the water supply passage 3, and a drain plug 32 is connected to a portion of the water supply passage 3 downstream of the stop valve 31.

[0015] A water reservoir 24 is recessed in the bottom of the cleaning tank 2. A cleaning / drainage pump 5 is provided in communication with the water reservoir 24, and a water level detector 6 is also provided in communication with the water reservoir 24 to detect the water level in the cleaning tank 2. When the cleaning / drainage pump 5 is rotated forward, cleaning water is circulated into the cleaning tank 2 via the cleaning nozzle 22, and when the cleaning / drainage pump 5 is rotated reversely, the cleaning water in the cleaning tank 2 is drained via a drainage channel 7. The drainage channel 7 is provided with an inverted U-shaped rising portion 71 for preventing backflow, an air vent portion 72, a drainage trap portion 73, and a check valve 74.

[0016] A drying fan 8 is provided within the exterior case 1, which blows drying air into the cleaning tank 2. A processing agent supplying device 4 and a controller 9 which controls the cleaning / drainage pump 5, heater 23 and drying fan 8 and also serves as control means for the processing agent supplying device 4 are provided within a hollow front door section 25 at the front of the cleaning tank 2, and an operation section 26 on which various switches such as a power switch and an operation switch are arranged is provided at the upper end of the front door section 25.

[0017] When the operation switch of the operation unit 26 is turned on, first, the detergent as the processing agent is supplied together with water by the processing agent supply device 4 to the cleaning tank 2 as the supply receiving part, and when the water level in the cleaning tank 2 reaches a predetermined water level and is detected by the water level detection device 6, the supply of the detergent and water is stopped. Next, the heater 23 is energized and the cleaning / drainage pump 5 is rotated forward to heat the cleaning water (water mixed with the detergent) and spray it from the cleaning nozzle 22, performing a cleaning operation for a predetermined time. After the cleaning operation is completed, the cleaning / drainage pump 5 is rotated in the reverse direction to drain the cleaning water in the cleaning tank 2, and then water is supplied to the cleaning tank 2 through the processing agent supply device 4 until the water level reaches a predetermined level, and then the cleaning / drainage pump 5 is rotated in the forward direction to spray water from the cleaning nozzle 22, performing a rinsing operation for a predetermined time. After the rinsing operation is completed, the cleaning / drainage pump 5 is rotated in the reverse direction to drain the water in the cleaning tank 2, and then the heater 23 is energized and the drying fan 8 is driven to perform a drying operation for a predetermined time.

[0018] The treatment agent supplying device 4 will be described below with reference to Fig. 2. The treatment agent supplying device 4 is capable of supplying a predetermined amount of detergent sucked out from a detergent storage tank 40 together with water to the cleaning tank 2. The treatment agent supplying device 4 is provided with a main passage 42 having a water supply valve 41 at its upstream end, which supplies water to the cleaning tank 2, and the downstream end of the water supply path 3 is connected to the water supply valve 41. The treatment agent supplying device 4 further includes a side flow passage 43 which introduces the detergent stored in the storage tank 40 into the main passage 42, a switching valve 44 as switching means disposed at the junction of the main passage 42 and the side flow passage 43, and a detergent suction unit 45.

[0019] The suction unit 45 is composed of a positive displacement pump 451 having an operating member 451c made of a piston, a plunger, a diaphragm, etc. that reciprocates via a crank mechanism 451b by a motor 451a, a first check valve 452 on the upstream side that allows only the flow sucked into the pump 451, and a second check valve 453 on the downstream side that allows only the flow pushed out from the pump 451. The suction unit 45 is interposed in a portion 42b of the main passage 42 downstream of the changeover valve 44. Also, a bypass passage 46 is provided that connects a portion 42a of the main passage 42 upstream of the changeover valve 44 with a portion of the main passage 42 downstream of the suction unit 45, and a negative pressure intake passage 47 that sucks air in the cleaning tank 2 into the upstream portion of the main passage 42 when the water supply passage 3 side becomes negative pressure for some reason. The negative pressure intake passage 47 is composed of a very thin pipe, and the pipe resistance is quite high, so that almost no water flows through it. In addition, instead of constructing the negative pressure intake passage 47 with a very thin pipe, backflow prevention measures may be taken, for example, by disposing a backflow prevention device such as a vacuum breaker or a pressure-reducing backflow preventer at the branch point from the main passage 42.

[0020] The switching valve 44 is switchable between a first state in which the portion 42a of the main passage 42 upstream of the switching valve 44 is blocked from communication with the portion 42b of the main passage 42 downstream of the switching valve 44 and the side flow passage 43 is connected to the portion 42b of the main passage 42 downstream of the switching valve 44, and a second state in which the portion 42a of the main passage 42 upstream of the switching valve 44 is connected to the portion 42b of the main passage 42 downstream of the switching valve 44 and the side flow passage 43 is blocked from communication with the portion 42b of the main passage 42 downstream of the switching valve 44. The switching valve 44 is normally in the second state and is switched to the first state when energized.

[0021] Before the above-mentioned cleaning operation, the controller 9, which is the control means of the treatment agent supply device 4, closes the water supply valve 41 and switches the switching valve 44 to a first state, and drives the pump 451 to perform a suction operation in which a predetermined amount of detergent is sucked out from the storage tank 40 toward the portion 42b of the main passage 42 downstream of the switching valve 44, and then opens the water supply valve 41 and switches the switching valve 44 to a second state, and performs a discharge operation in which the predetermined amount of detergent sucked out in the suction operation is discharged together with water via the main passage 42 to the cleaning tank 2.

[0022] The discharge operation is ended when the amount of water supplied to the washing tank 2 reaches a predetermined amount, the water level in the washing tank 2 reaches the predetermined water level, and the water level detection device 6 detects this. Here, the main passage 42 has a high pipe resistance due to the switching valve 44, so that water is likely to flow into the bypass passage 46 during the discharge operation. As a result, even if the total amount of water supplied to the washing tank 2 through the main passage 42 and the bypass passage 46 reaches the predetermined amount, the amount of water flowing through the main passage 42 may be insufficient, and a part of the predetermined amount of detergent sucked out during the suction operation may remain in the main passage 42. Therefore, the bypass passage 46 is provided with an orifice 461 as a throttling means for throttling the flow rate of water flowing through the bypass passage 46. The ratio of the amount of water supplied to the washing tank 2 through the main passage 42 to the amount of water supplied to the washing tank 2 through the main passage 42 and the bypass passage 46 during the discharge operation is set to be equal to or greater than the value required to discharge all of the predetermined amount of detergent.

[0023] Next, a description will be given of a treatment agent supplying device 4 according to a second embodiment of the present invention shown in Fig. 3. The same members and parts as those of the treatment agent supplying device 4 according to the first embodiment shown in Fig. 2 are denoted by the same reference numerals as above. The differences between the second embodiment of the treatment agent supplying device 4 and the first embodiment are that a suction unit 45 is provided in a bypass path 46 provided to connect a portion 42a of the mainstream passage 42 upstream of the switching valve 44 and a portion 42b of the mainstream passage 42 downstream of the switching valve 44, and that the switching valve 44 is switchable between a first state in which the communication between the portion 42a of the mainstream passage 42 upstream of the switching valve 44 and the portion 42b of the mainstream passage 42 downstream of the switching valve 44 is blocked and the by-flow passage 43 is connected to the portion 42a of the mainstream passage 42 upstream of the switching valve 44, and a second state in which the communication between the portion 42a of the mainstream passage 42 upstream of the switching valve 44 and the portion 42b of the mainstream passage 42 downstream of the switching valve 44 is connected and the by-flow passage 43 is connected to the portion 42a of the mainstream passage 42 upstream of the switching valve 44.

[0024] In the second embodiment, the pump 451 is driven with the water supply valve 41 closed and the switching valve 44 switched to the first state to perform a suction operation in which a predetermined amount of detergent is sucked out from the storage tank 40 toward the portion 42a of the main passage 42 upstream of the switching valve 44, and the water supply valve 41 is opened and the switching valve 44 is switched to the second state to perform a delivery operation in which the predetermined amount of detergent sucked out in the suction operation is delivered together with water via the main passage 42 to the cleaning tank 2.

[0025] A storage section 421 for storing the detergent sucked out during the suction operation is provided in the portion 42a of the main passage 42 upstream of the switching valve 44. During the suction operation, the detergent is prevented from reaching the suction unit 45. However, instead of providing the storage section 421, it is also possible to increase the length of the portion 42a of the main passage 42 upstream of the switching valve 44 so that the detergent does not reach the suction unit 45.

[0026] In addition, an orifice 461 serving as a throttle means is provided in the bypass passage 46 downstream of the suction unit 45. The ratio of the amount of water supplied to the washing tank 2 via the main passage 42 to the amount of water supplied to the washing tank 2 via the main passage 42 and the bypass passage 46 during the discharge operation is set to be equal to or greater than the value required to discharge all of the predetermined amount of detergent sucked out during the suction operation.

[0027] Next, a treatment agent supplying device 4 according to a third embodiment of the present invention shown in Fig. 4 will be described. The same members and parts as those of the treatment agent supplying device 4 according to the first embodiment shown in Fig. 2 are denoted by the same reference numerals as above. The treatment agent supplying device 4 according to the fourth embodiment differs from that according to the first embodiment in that an on-off valve 48 as second switching means that can be switched between an open state that allows water to pass through the bypass path 46 and a cut-off state that prevents water from passing through the bypass path 46 is provided in the bypass path 46, instead of the orifice 461 of the first embodiment. The on-off valve 48 is normally in an open state, and is switched to a cut-off state when current is applied.

[0028] The controller 9 (see FIG. 1), which is a control means of the treatment agent supplying device 4, switches the on-off valve 48 to an open state during a rinsing operation in which only water is supplied to the cleaning tank 2, and supplies water to the cleaning tank 2 also through the bypass passage 46. This makes it possible to shorten the time required for a specified amount of water to be supplied to the cleaning tank 2. On the other hand, during a delivery operation, the on-off valve 48 is switched to a closed state. This prevents water from flowing through the bypass passage 46, so that the specified amount of water supplied to the cleaning tank 2 flows only through the main passage 42, and all of the specified amount of treatment agent sucked into the main passage 42 during the suction operation can be delivered from the main passage 42. This makes it possible to prevent a portion of the specified amount of treatment agent sucked out during the suction operation from remaining in the main passage 42 during the delivery operation. The on-off valve 48 may be kept open except during the delivery operation, including the rinsing operation, and may be kept closed except during the rinsing operation.

[0029] In the third embodiment, the bypass passage 46 is provided with the on-off valve 48 as the second switching means, but a three-way valve as the second switching means may be provided at a branch point between the part 42a of the main passage 42 upstream of the switching valve 44 and the bypass passage 46, or at a junction between the part of the main passage 42 downstream of the suction unit 45 and the bypass passage 46. This three-way valve always connects the upstream part and downstream part of the main passage 42 from the three-way valve, and is freely switchable between a state in which the bypass passage 46 is connected to the main passage 42 and a state in which this connection is blocked. By connecting the bypass passage 46 to the main passage 42, the bypass passage 46 is in an open state that allows water to pass through the bypass passage 46, and by blocking this connection, the bypass passage 46 is in a blocked state that prevents water from passing through the bypass passage 46.

[0030] Although the embodiment of the present invention has been described above with reference to the drawings, the present invention is not limited thereto. For example, the dishwasher of the above embodiment is a dishwasher with a drying function equipped with a drying fan 8, but may be a dishwasher without a drying function. In addition, the treatment agent supplying device 4 of the above embodiment supplies a detergent as a treatment agent to the washing tub 2 as a supplying part of the dishwasher, but may supply a rinse as a treatment agent. In addition, the present invention can be similarly applied to other uses, for example, a treatment agent supplying device that supplies a detergent or fabric softener as a treatment agent to the washing tub as a supplying part of a washing machine. [Explanation of symbols]

[0031] 2...cleaning tank (supplied part), 4...treatment agent supply device, 40...storage tank, 41...water supply valve, 42...main stream passage, 42a...portion of the main stream passage upstream of the switching means, 42b...portion of the main stream passage downstream of the switching means, 43...side flow passage, 44...switching valve (switching means), 45...suction unit, 451...pump, 452...first check valve, 453...second check valve, 46...bypass path, 461...orifice (throttling means), 48...opening / closing valve (second switching means), 9...controller (control means).

Claims

1. A treatment agent supplying device capable of supplying a predetermined amount of treatment agent sucked out from a storage tank of the treatment agent together with water to a supply target portion, the system comprises a main passage having a water supply valve at an upstream end for supplying water to a supply portion, a side passage for introducing a treatment agent stored in a storage tank into the main passage, a switching means disposed at a junction of the main passage and the side passage, a treatment agent suction unit, and a control means; The suction unit is composed of a positive displacement pump, a first check valve on the upstream side that allows only a flow to be sucked into the pump, and a second check valve on the downstream side that allows only a flow to be pushed out from the pump, and the suction unit is interposed in a portion of the mainstream passage on the downstream side of the switching means, and a bypass path is provided that connects the portion of the mainstream passage on the upstream side of the switching means and the portion of the mainstream passage on the downstream side of the suction unit, the switching means is switchable between a first state in which the switching means interrupts communication between a portion of the mainstream passage upstream of the switching means and a portion of the mainstream passage downstream of the switching means and connects the byflow passage with the portion of the mainstream passage downstream of the switching means, and a second state in which the switching means connects the portion of the mainstream passage upstream of the switching means and a portion of the mainstream passage downstream of the switching means and disconnects communication between the byflow passage and the portion of the mainstream passage downstream of the switching means, the control means is configured to execute a suction operation in which the control means closes the water supply valve and switches the switching means to a first state to drive the pump to suction a predetermined amount of the treatment agent from the storage tank toward a portion of the mainstream passage downstream of the switching means, and a delivery operation in which the control means opens the water supply valve and switches the switching means to a second state to deliver the predetermined amount of the treatment agent sucked out in the suction operation to a supply portion together with water through the mainstream passage, a throttling means for throttling the flow rate of water flowing through the bypass passage, so that the ratio of the amount of water supplied to the supply destination through the mainstream passage to the amount of water supplied to the supply destination through the mainstream passage and the bypass passage during a discharge operation is equal to or greater than the value required to discharge all of a predetermined amount of the treatment agent.

2. A treatment agent supplying device capable of supplying a predetermined amount of treatment agent sucked out from a storage tank of the treatment agent together with water to a supply target portion, the system comprises a main passage having a water supply valve at an upstream end for supplying water to a supply portion, a side passage for introducing a treatment agent stored in a storage tank into the main passage, a switching means disposed at a junction of the main passage and the side passage, a treatment agent suction unit, and a control means; The suction unit is composed of a positive displacement pump, a first check valve on the upstream side that allows only a flow to be sucked into the pump, and a second check valve on the downstream side that allows only a flow to be pushed out from the pump, and the suction unit is interposed in a bypass path provided to connect a portion of the mainstream passage on the upstream side of the switching means to a portion of the mainstream passage on the downstream side of the switching means, the switching means is switchable between a first state in which the switching means interrupts communication between a portion of the main passage upstream of the switching means and a portion of the main passage downstream of the switching means and connects the byflow passage with the portion of the main passage upstream of the switching means and a second state in which the switching means connects the portion of the main passage upstream of the switching means and a portion of the main passage downstream of the switching means and interrupts communication between the byflow passage and the portion of the main passage upstream of the switching means, the control means is configured to execute a suction operation in which the control means closes the water supply valve and switches the switching means to a first state to drive the pump to suction a predetermined amount of the treatment agent from the storage tank toward a portion of the mainstream passage upstream of the switching means, and a delivery operation in which the control means opens the water supply valve and switches the switching means to a second state to deliver the predetermined amount of the treatment agent sucked out in the suction operation to a supply portion together with water through the mainstream passage, A treatment agent supplying device characterized in that a throttling means for throttling the flow rate of water flowing through the bypass passage is provided in a portion of the bypass passage downstream of the suction unit, so that the proportion of the amount of water supplied to the supplying part through the mainstream passage out of a predetermined specified amount of water supplied to the supplying part through the mainstream passage and the bypass passage during a discharge operation is equal to or greater than the value required to discharge all of a predetermined amount of treatment agent.

3. A treatment agent supplying device capable of supplying a predetermined amount of treatment agent sucked out from a storage tank of the treatment agent together with water to a supply target portion, the system comprises a main passage having a water supply valve at an upstream end for supplying water to a supply portion, a side passage for introducing a treatment agent stored in a storage tank into the main passage, a switching means disposed at a junction of the main passage and the side passage, a treatment agent suction unit, and a control means; The suction unit is composed of a positive displacement pump, a first check valve on the upstream side that allows only a flow to be sucked into the pump, and a second check valve on the downstream side that allows only a flow to be pushed out from the pump, and the suction unit is interposed in a portion of the mainstream passage on the downstream side of the switching means, and a bypass path is provided that connects the portion of the mainstream passage on the upstream side of the switching means and the portion of the mainstream passage on the downstream side of the suction unit, the switching means is switchable between a first state in which the switching means interrupts communication between a portion of the mainstream passage upstream of the switching means and a portion of the mainstream passage downstream of the switching means and connects the byflow passage with the portion of the mainstream passage downstream of the switching means, and a second state in which the switching means connects the portion of the mainstream passage upstream of the switching means and a portion of the mainstream passage downstream of the switching means and disconnects communication between the byflow passage and the portion of the mainstream passage downstream of the switching means, the control means is configured to execute a suction operation in which the control means closes the water supply valve and switches the switching means to a first state to drive the pump to suction a predetermined amount of the treatment agent from the storage tank toward a portion of the mainstream passage downstream of the switching means, and a delivery operation in which the control means opens the water supply valve and switches the switching means to a second state to deliver the predetermined amount of the treatment agent sucked out in the suction operation to a supply portion together with water through the mainstream passage, a second switching means is provided in either the bypass passage, a branching portion between the bypass passage and a portion of the main passage upstream of the switching means, or a joining portion between the bypass passage and a portion of the main passage downstream of the suction unit; the second switching means is switchable between an open state that allows water to pass through the bypass passage and a blocked state that prevents water from passing through the bypass passage; A treatment agent supplying device characterized in that the control means switches the second switching means to an open state during operation in which only water is supplied to the supply part, but switches the second switching means to a blocked state at least during a discharge operation.

4. A dishwasher equipped with a washing tub for storing tableware, the washing tub being equipped with a treatment agent supplying device capable of supplying a predetermined amount of detergent sucked out from a storage tank of the detergent as a treatment agent together with water to the washing tub as a receiving part, the dishwasher being characterized in that the treatment agent supplying device is configured as described in any one of claims 1 to 3.

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