JPH07322991A - Back flow preventing structure for drain circuit of apparatus - Google Patents

Abstract

PURPOSE:To simplify the structure and improve the efficiency of the assembling work by obviating a special seal member for sealing the outer periphery of a sleeve and a pipe connection section in a back flow preventing mechanism inserting the sleeve into the drain pipe connection section provided at the downstream end of a drain circuit from a downstream end opened section and fitted with a valve element for preventing a back flow to the sleeve. CONSTITUTION:A circular wall 78 is protruded in the center direction at the upstream end of the sleeve storage section of a drain pipe connection section 76, and a valve element 94 is brought into contact with the downstream side wall face serving as a valve seat section. The valve element 94 is molded integrally with a fitting arm 95 provided at part of its peripheral edge with an elastic member such as rubber, the tip section of the fitting arm 95 is held between a sleeve 9 and the pipe connection section 76, and the sleeve 9 is connected to the pipe connection section 76 in the release stop state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backflow prevention mechanism for a drainage circuit in a water-using device, and can be applied to, for example, a drainage circuit provided in a dishwasher.

[0002]

2. Description of the Related Art In a water-using appliance such as a dishwasher equipped with a drainage circuit for draining used cleaning water, a backflow prevention mechanism for preventing backflow of dirty water downstream of the drainage circuit into the appliance. Is incorporated in the drainage circuit. FIG. 8 shows a dishwasher as a specific example of a water-using appliance.

In this structure, a nozzle arm (6) having a large number of nozzles (60) (60) is provided in the cleaning chamber (2) which is opened and closed by the opening / closing door (3), and the cleaning chamber is also provided. A storage tank (23) for storing wash water is formed at the bottom of (2). The filtration container (7) connected to the bottom wall of the storage tank (23) and the nozzle arm (6) are provided with a washing pump (62).
They are connected by (F). Further, a drainage circuit (74) including a drainage pump (75) is connected to the bottom wall of the storage tank (23), and a drainage pipe connecting portion (7) located at the downstream end of the drainage circuit (74).
A backflow prevention mechanism (77) is incorporated in 6).

FIG. 7 shows a conventional backflow prevention mechanism (77), which is a cylindrical sleeve inserted in the drain pipe connecting portion (76).
An O-ring (91) is fitted on the outer circumference of the upstream end of (9). In addition, insert the slipper (9
3) is formed, and the insertion slid (93) has an inverted L-shaped hanging arm (95) protruding above the rubber valve body (94).
Is inserted and the upper bent portion is engaged with the upper surface of the sleeve (9). The valve body (94) is arranged so as to open and close the valve seat opening (96) formed by narrowing the inner diameter of the sleeve (9) from the downstream side. The sleeve (9) has an annular wall (7) protruding to the inner peripheral surface in the vicinity of the downstream end of the drainage pipe connecting portion (76).
8) is in contact with the sleeve from the downstream side.
(9) is prevented from moving upstream.

In this case, when an operation switch (not shown) is operated, the cleaning water in the storage tank (23) is pressure-fed to the nozzle arm (6) by the cleaning pump (62) in the water passage (F), and the cleaning water is discharged. The tableware (M) (M) is sprayed from the nozzles (60) (60) to wash the tableware (M) (M). When the cleaning operation is completed, the drainage pump (75) operates and the storage tank (23)
The dirty cleaning water in the inside is discharged to the outside of the machine through the backflow prevention mechanism (77) portion provided in the drain pipe connection portion (76) of the drain circuit (74).
That is, the wash water flowing downstream in the drainage circuit (74) is discharged to the outside of the machine by opening the valve body (94) in the sleeve (9) to the downstream side by the water pressure and passing through the portion. Of. Further, in the above-mentioned one, since the backflow prevention mechanism (77) is incorporated in the drainage circuit (74), dirty water in the drainage hose (not shown) connected to the water distribution pipe connection part (76) is washed ( 2) The inconvenience of backflow to the side can be prevented.

However, in the above-mentioned conventional one, the boundary between the inner circumference of the drain pipe connecting portion (76) and the sleeve (9) is an O-ring.
Without sealing with (91), it is not possible to completely prevent the reverse flow of sewage through the gap between the two and the O-ring (9
Since 1) is indispensable, there is a disadvantage that the number of parts increases and the structure becomes complicated. There is also a problem that the efficiency of assembly work is hindered as the number of parts increases.

The present invention has been made in view of the above points, and "the drain pipe connecting portion (76) provided at the downstream end of the drain circuit (74).
Insert the sleeve (9) inside from the open end of the downstream end and
In this backflow prevention mechanism in which a valve body (94) for backflow prevention is equipped in this sleeve (9), a special sealing member for sealing the outer circumference of the sleeve (9) and the pipe connection part (76) is provided. It is an object of the present invention to simplify the structure and improve the efficiency of the assembling work by making it unnecessary.

[0008]

[Technical Means] The technical means of the present invention for solving the above-mentioned problem is to provide an annular wall (78) at the upstream end of the sleeve accommodating portion of the drain pipe connecting portion (76) so as to project in the center direction. A valve body (94) is brought into contact with the valve seat by using the downstream side wall surface as a valve seat portion, and the valve body (94) is attached to a part of a peripheral edge of the mounting arm (9
5) is integrally molded with an elastic material such as rubber, and the tip of this mounting arm (95) is connected to the sleeve (9) and the pipe connection (76).
And the sleeve (9) is connected to the pipe connecting part (76) so as not to be pulled out. ”

[0009]

The above technical means operates as follows. Disc (9
The tip of the mounting arm (95) of 4) is attached to the sleeve (9) and the water pipe connection (7
It is press-fitted and fixed between 6), whereby the valve body (94)
Is still attached to the upper wall of the sleeve (9) without falling off. And in this mounted state,
The valve body (94) attached to the upstream end of the sleeve (9) is brought into contact with the valve seat on the downstream side wall surface of the annular wall (78) projecting toward the center of the drain pipe connecting part (76), and the central hole is formed. Block from the upstream side.
Therefore, when drainage flows from the upstream side of the drainage circuit (74), the mounting arm (95) is deformed by the pressure of the drainage so that the valve body (94) separates from the annular wall (78) to the downstream side. As a result, drainage flows downstream through the central hole of the annular wall (78). Conversely, when the pressure on the downstream drain hose side connected to the water distribution pipe connection (76) becomes high, the valve body (94) causes the annular wall (7
It is kept in contact with 8), so that the dirty water in the drain hose does not flow back.

[0010]

[Effect] The present invention has the following unique effects. The central hole of the annular wall (78) formed on the inner peripheral surface of the drainage pipe connecting part (76) is inserted into the valve body.
Since it is opened and closed by (94), it is not necessary to interpose a special sealing material such as the above-mentioned conventional O-ring between the outer circumference of the sleeve (9) and the drain pipe connecting portion (76). Therefore, the number of required parts is reduced by the amount that the special sealing material is unnecessary,
The assembling work can be simplified.

[0011]

Embodiments of the present invention described above will now be described in detail with reference to the drawings. The dishwasher of FIG. 1 is the same as that of FIG. 8 except that a U-shaped sealing water pipe (72) that is convex downward is provided near the downstream end of the drainage circuit (74). It is similarly configured.

The contents described in the above-mentioned conventional example will be omitted below. Cleaning chamber (2) formed in the casing (1)
A storage tank (23) is formed at the bottom of the storage tank (23).
A filtration container (7) for removing the residue is connected to the column, and a drainage circuit (74) having a drainage pump (75) is connected to the bottom of the filtration container (7). Then, in the vicinity of the downstream end of the drainage circuit (74), the water sealing portion (7
The water-sealing pipe (72) which forms 20) is connected, and the drain pipe connecting portion (76) is connected to the further downstream end of the water-sealing pipe (72).

As shown in FIG. 2, the drain pipe connecting portion (76) is internally provided with a sleeve (9) to which a rubber valve body (94) whose mounting arm (95) is deformable is attached. The valve body (94) is composed of a disc-shaped valve portion (941) and a mounting arm (95) protruding from the upper portion thereof, and the upper end portion of the mounting arm (95) is bent to the downstream side to form a bent engagement portion. (940) is formed. Also, the bending engagement portion (9
An engaging hole (942) penetrating vertically is bored in 40).

As shown in FIGS. 3 and 4, the sleeve (9) for loading the valve body (94) is formed with a notch (90) opening toward the upstream side, and The width of the notch (90) is set to be slightly larger than the width of the mounting arm (95) provided on the valve body (94). Further, an engaging projection (99) located near the upstream side of the notch (90) is provided on the upper surface of the sleeve (9), and the engaging projection (99) is formed on the valve body (94). An engaging hole (942) formed in the bending engaging portion (940) is adapted to be externally fitted and engaged. Further, on the upstream side of the lower part of the sleeve (9), the mounting arm (95) of the valve element (94) faces upward when engaged with the constituent wall of the drain pipe connecting part (76) described later. The positioning notch (89) for performing the positioning function is opened, and the sleeve (9) has elastic legs (87) located between the slits (88) (88) formed by cutting from the downstream end side thereof. Is provided. Then, a protrusion (9
7) is projected. The elastic leg (87) is 18
Two pieces are provided at an interval of 0 degree and project further downstream than other portions. Then, by projecting in this manner, the sleeve (9) can be easily removed from the drain pipe connecting portion (76).

The inner peripheral surface of the drain pipe connecting portion (76) is provided with engaging concave portions (760) formed at intervals of 180 degrees, and at the inner surface of the portion continuing to the downstream side of the annular wall (78). Engagement step (7
9) is provided. Next, an operation of assembling the backflow prevention mechanism (77) using the above-mentioned components will be described.

First, the engagement hole (942) formed in the bending engagement portion (940) of the mounting arm (95) protruding from the valve body (94) is fitted with a sleeve.
The engaging projection (99) protruding from the upper surface of (9) is externally fitted and engaged.
Then, the bending engagement portion (940) of the valve body (94) is
The state is fitted in the notch (90) cut in the upper upstream end of (9), and the valve portion (941) of the valve body (94) is positioned substantially concentrically with the sleeve (9).

Next, when the sleeve (9) is inserted into the drain pipe connecting portion (76) from the valve body (94) side attached to the sleeve (9), the positioning notch (lowering position) formed at the lower end of the upstream end of the sleeve (9) ( 89) and the corresponding engagement step (79) on the drain pipe connection (76) side engage in a non-rotatable state, and the protrusion (7) protruding from the elastic leg (87) of the sleeve (9). 97) and the corresponding engaging recess (760) on the drain pipe connecting portion (76) side are engaged as shown in FIG. 6, whereby the sleeve (9) equipped with the valve body (94) is connected to the drain pipe. It is fixed in the part (76). Further, in this state, as shown in FIG. 2, the downstream side wall surface of the annular wall (78) of the drain pipe connecting portion (76) is in a closed state in which the valve body (94) is in contact with the downstream side. Become. And
In the above embodiment, the valve body (94) attached to the upstream end of the sleeve (9) is used for the valve seat opening (98) in the drain pipe connection (76).
Since it is configured to open and close (the through hole surrounded by the annular wall (78)), the outer circumference of the sleeve (9) and the drain pipe connecting portion (7
Even if the space between 6) is not sealed, water does not leak between the drainage pipe connecting part (76) and the water sealing pipe (72) through the portion. Therefore, it is not necessary to provide an O-ring for sealing on the outer periphery of the sleeve (9) as in the conventional case described above, and the number of required parts is reduced.

Next, another structure of the dishwasher shown in FIG. 1 will be briefly described. A water passage (F) equipped with a washing pump (62) is connected to the trunk of the filtration container (7) that projects downward from the storage tank (23) formed in the lower part of the washing chamber (2). It is assumed that the downstream end of the water passage (F) is connected to the nozzle arms (6) and (6) arranged in upper and lower two stages (only the lower nozzle arm (6) is shown in FIG. 1). Along with the nozzle arm (6), there is mounted (4) which is supported by a rail (R) so that it can be pulled out. Further, an air supply circuit (83) having a fan (8) for supplying outside air is connected to the back wall (29) of the cleaning room (2), and the ceiling wall (28) of the cleaning room (2) is connected. Has
Exhaust passage for discharging the moist air in the cleaning chamber (2) to the outside of the machine
(5) is connected.

Next, the actual use of the dishwasher will be described. When the tableware (M) (M) is stored in the rack (4) and this rack (4) is loaded into the washing chamber (2) and the washing operation is performed in this state, the washing chamber (2) The cleaning water in the storage tank (23), which is supplied from the water supply pipe (25) connected to the rear wall (29) and is warmed by the heater (20), is pumped through the filtration container (7).
It is sucked by (62) and sent under pressure to the nozzle arm (6), and is sprayed from the nozzles (60) (60) onto the dishes (M) (M) to be washed.

When the cleaning operation is completed, the drainage pump (75)
Is activated, and dirty cleaning water in the storage tank (23) is drained (74).
Is sent to the downstream end of. Then, the wash water flowing in the drainage circuit (74) exerts a water pressure on the valve body (94) loaded in the drainage pipe connection part (76) to bend the mounting arm (95), whereby the valve body is bent. (94) is pushed open to the downstream side as shown by the imaginary line in FIG. As a result, the cleaning water is drained pipe connection (76)
It is discharged to the sewage side via a drain hose (not shown) connected to the. Then, when this drainage operation is completed, the valve body (94) returns to the closed state in which the valve seat opening (98) is closed again due to gravity and the elastic force of the mounting arm (95). Prevent sewage from flowing back to the washing room (2) side. Further, in this embodiment, since the water sealing part (720) is formed in the water sealing pipe (72) connected to the upstream side of the drainage pipe connecting part (76), the water sealing part (720) after drainage is provided. Is the water seal as shown by the imaginary line in Figure 2.
(W) will be accumulated, and there will be no inconvenience that the odor on the sewage side will flow into the cleaning chamber (2).

In the above embodiment, the sleeve (9) has a protrusion.
(97) is provided, and the engaging recess (760) with which this is engaged is formed in the pipe connecting part (76) .On the contrary, the protrusion (97) projects on the inner surface of the pipe connecting part (76). Alternatively, the engaging recess (760) may be formed on the outer surface of the sleeve (9). Further, in the above embodiment, the protrusion (99) protruding from the upper surface of the sleeve (9) and the engaging hole (942) formed in the bending engaging portion (940) of the mounting arm (95) of the valve body (94).
Although these are connected by engaging with each other, the bending engagement portion (9) that bends from the mounting arm (95) of the valve body (94) is used.
40) may be provided with a downward projection, and an engagement hole with which the projection is engaged may be formed in the upper wall near the tip of the sleeve (9).

[Brief description of drawings]

FIG. 1 is a partial sectional view of a dishwasher incorporating a backflow prevention mechanism (77) according to an embodiment of the present invention.

[Fig. 2] Enlarged cross-sectional view near the drain pipe connection (76)

FIG. 3 is an exploded sectional view of a main part

[Figure 4] Front view of the sleeve (9)

FIG. 5 is a front view of the valve body (94).

FIG. 6 is a cross-sectional view of the drain pipe connecting portion (76) in a state where the sleeve (9) and the like are loaded.

FIG. 7 is an explanatory diagram of a conventional example.

FIG. 8 is an explanatory diagram of a conventional example.

[Explanation of symbols]

 (9) ・ ・ ・ Sleeve (74) ・ ・ ・ Open end of downstream end (76) ・ ・ ・ Piping connection (78) ・ ・ ・ Annular wall (94) ・ ・ ・ Valve

Claims (2)

[Claims] A sleeve (9) is inserted from a downstream end open portion into a drain pipe connecting portion (76) provided at a downstream end of a drainage circuit (74), and a valve for preventing backflow is provided in the sleeve (9). In a backflow prevention mechanism equipped with a body (94), an annular wall (78) is projected toward the center at the upstream end of the sleeve accommodating portion of the drainage pipe connecting portion (76), and the downstream side wall surface is valved. The valve body (94) is brought into contact with the valve seat as a seat portion, and the valve body (94) is integrally molded with an elastic material such as rubber together with a mounting arm (95) continuously provided on a part of the peripheral edge of the valve body (94). Sleeve the tip of this mounting arm (95).
A backflow prevention structure in a drainage circuit of a device in which a sleeve (9) is held between the pipe connection part (76) and the pipe connection part (76), and the sleeve connection part (76) is connected to the pipe connection part (76) in a retaining state. 2. An elastic leg (87), which is located between the slits (88) (88) open to the downstream end surface of the sleeve (9) and has a protrusion or an engaging recess on the outer surface, and a pipe connection. The sleeve is provided with an engaging recess or a protrusion formed on the inner surface of the sleeve (76).
The drainage circuit of the device according to claim 1, wherein when the (9) is inserted into the pipe connecting part (76), the protrusions are fitted into the engaging recesses so as to connect them in a retaining state. Backflow prevention structure.