GB2039002A - A flood control arrangement for dishwashers - Google Patents

Abstract

The arrangement includes a sealing plunger 62 disposed in a plunger body member housing 60 installed downstream of a water fill valve 42. The sealing plunger tends to be moved to the sealing position by the line water pressure to shut off inflow to the dishwasher but is blocked from movement to this position whenever the water level is below the flood level by the stem 78 of a float 82 positioned in the dishwasher tub 26. When the water level in the tub approaches the flood level, the float rises in the tub to a position whereat the float stem releases the sealing plunger to allow it to move to the sealing position and shut off further flow to the dishwasher. The float stem either causes the sealing plunger to be tilted off a sealing face or prevents it from moving laterally in the line to the sealing position in order to produce the blocking action. <IMAGE>

Description

SPECIFICATION Flood control for a dishwasher Modern automatic dishwashers generally include an automatic control of in-flow of water from the water supply into the machine. This automatic control is typically provided by a timer which causes a fill valve to be opened at the appropriate point in the machine cycle for a predetermined time interval, allowing water flow into a dishwasher tub over this interval. Such automatic control creates the possibility of a flooding condition being reached in which water overflows the level of the tub and out of the machine where it may cause damage. Such a flooding condition may occur for a variety of reasons, such as failure of the fill valve, over pressure line conditions, clogged dishwasher drain, etc. Many dishwasher designs accordingly provide for some arrangement for flood control.

In some of these designs, a fail-safe mechanism is incorporated into the electrical control which will correct flood level conditions occurring during the machine cycle. Some failure mcdes, however, such as a mechanical failure of the valve may occur at any time, not only during the machine operation. Thus a 24-hour flood control protection is a desirable feature in such machines.

In U. S. Patent No. 3,894,555, a flood control feature is disclosed in which a float is mounted within the dishwasher tub which acts to deenergize a secondary electrically operated valve installed downstream from the fill valve. If a flood level occurs in the tub, the float rises to the flood level and acts to operate an associated switch to open the circuit to the secondary flood control valve, causing closing of the valve and cessation of flow to the tub.

The secondary valve adds significantly to the expense of manufacture, since an additional relatively costly electrically operated valve is required. In addition, the reliability of electrically operated valves is less than mechanically operated valves and any failure of the valve will cause either malfunction of the dishwasher or defeat of the flood control feature.

In accordance with the present invention there is provided a flood control arrangement for preventing flooding of liquid from a container, the arrangement comprising: control valve means interposed in a line supplying liquid to the container, the valve means including a sealing plunger disposed in a housing formed with an inlet chamber for the liquid being supplied to the container, and'the head of the plunger being disposed in the inlet chamber such that liquid pressure in the chamber is able to move the head into sealing engagement with a valve seat; and float disposed in the container such that the position of the float is dependent on the level of the liquid in the container; und a blocking member normally blocking movement of the plunger into its sealing position, the blocking member being connected to the float such that the plunger is released for movement only when the liquid in the container reaches a predetermined level.

In a washing machine embodying the invention, the flood control valve means is preferably located downstream of an electrically operated solenoid valve, the machine also including means directing water from the outlet of the solenoid valve into a water collecting tub.

In one embodiment of the invention, movement of the plunger into its sealing position is blocked by a float stem normally positioned against the end of a stem extending from the plunger head and thereby preventing the head from being moved against the valve seat.

In a second embodiment of the invention, the float stem engages one side of the plunger stem so that the stem is tilted and misaligned with the valve seat.

By way of example only, some examples of the invention will now be described with reference to the accompanying drawings in which: FIGURE 1 is a fragmentary view of a dishwasher in front elevation shown in partial section to depict the relationship of the components of the present invention to the dishwasher structure.

FIGURE 2 is a view in partial section of the major components of the flood control arrangement according to the present invention as shown in FIGURE 1.

FIGURES 3 and 4 are sectional views of the sealing plunger and associated plunger housing, depicting the alternate versions of the present invention.

Referring to the drawings and particularly FIGURE 1, a conventional dishwasher 10 is depicted into which is incorporated the flood control arrangement according to the present invention. The dishwasher illustrated is of the builtin cabinet style, installed between adjacent kitchen cabinetry 12. The dishwasher 10 includes an inner frame 14 to which is mounted the outer cabinet panel 16 which provides access to the operating components, and front mounted access door 1 8 provides access to the interior 20 of the dishwasher.

In the dishwasher interior 20 are mounted one or more racks 22 adapted to receive the dishware items to be washed. Such racks 22 are mounted on rollers 24 for in and out movement for convenient loading of the dishware items.

The lower region of the interior 20 is comprised of a tub 26 which acts to collect the water introduced into the machine and directed in a high pressure spray at the dishware items. The washing action is carried out by means of a rotary spray arm 28 into which is circulated water under high pressure in order to wash and rinse the dishware items disposed in racks 22.

The water collected in tub 26 is directed through an inlet fitting 30 to the inlet side of a pump 32, driven by an electric motor 34.

The outlet 36 of pump 32 communicates with internal flow passages to provide the high pressure circulation to the rotary spray arm 28 during the wash and rinse cycles.

After the wash and rinse cycles, the water in the tub 26 is pumped via drain outlet 38 to a plumbing drain.

In order to provide the proper volume of water necessary for the wash and rinse cycles, an automatic fill arrangement is provided for introducing the water from the hot water connection into the machine. This arrangement conventionally includes a hot water pipe shown partially at 40 in communication with the hot water supply. The hot water pipe 40 is in fluid communication with a fill valve assembly 42 which is solenoid operated to establish a timed interval of communication at the appropriate points in the machine cycle with a fill hose 44, which extends upwardly along the dishwasher cabinetry and is placed in communication with a fill nozzle fitting 46 which directs the hot water into the interior of the machine during the fill cycle.

The flood control arrangement, according to the present invention, acts to mechanically prevent water flow from the fill valve assembly 42 into the tub 26 whenever flood conditions within the tub 26 are approached.

The flood control arrangement as seen in FIGURE 2 consists of the combination of a flood control valve 48 and a float assembly 50. The flood control valve 48 is in fluid communication with the fill hose 44 and the fill valve assembly 42.

A short length of hose 52 joins the outlet fitting 54 of the fill valve assembly 42 and an inlet fitting 56 of the flood control valve 48. The outlet of the flood control valve 48 is secured to the fill hose 44 to thus be placed in fluid communication with the fill circuit downstream of the fill valve assembly 42.

The flood control valve 48 consists of a plunger housing 60 within which is movably mounted a sealing plunger 62. The plunger housing 60 is formed with a relatively large diameter inlet chamber 64 which receives a sealing head 66 portion of the sealing plunger 62. A stem 68 of the sealing plunger 62 extends into an elongated passage 70 in communication with the inlet chamber 64 and of a larger diameter than the stem 68 to allow water flow between the stem 68 and the passage 70. Sealing head 66 is maintained in position in the inlet chamber 64 with a plurality of circumferentially spaced webs 72 which allows flow around the sealing head 66 and into the passage 70 with the sealing plunger 62 held in position as shown in FIGURE 2.

The effective inlet water pressure received from the fill valve assembly 42 acts on the sealing head 66 and urges the sealing plunger 62 to the right as viewed in FIGURE 2. A valve seating surface 74 is provided on the opposite face of the sealing head 66 from the direction of water pressure and is adapted to engage an annular surface 76 formed on the end wall of the inlet chamber 64, such that upon movement into engagement therewith, shutoff of the water flow downstream of the flood control valve 48 is provided.

The sealing plunger 62 is maintained in its unseated position shown in FIGURE 2 by blocking means including a float stem member 78 having its end portion positioned in abutment with the end face 80 of the stem 68. The float stem member 78 moves with a float 82 positioned in the bottom of tub 26, with the float stem member 78 passing through the interior opening 84 of a float guide 86. Float guide 86 extends upwardly over the flood level indicated at line 88 such that water will not flow through the interior opening 84 through which the float stem member 78 enters.

A seal 79 is provided in the plunger housing 60 which prevents the water from passing out between the float stem member 78 and the plunger housing 60.

Surrounding the float 82 is a protective float housing 90 with inlet cutouts 92 provided to enable the water to pass into the interior of the float housing 90. Float 82 is provided with an annular bell chamber 94 with an inner opening 96 provided adjacent the float guide 86 to enable the venting of the air and allowing the water level to thereby rise to the interior 98 of the float housing 90.

The float guide 86 also insures guiding movement of the float to prevent tipping movement.

The relative weight and buoyancy of the float 82 is such that it will not rise in the housing appreciably until the flood level indicated at line 88 is approached. At this point, the buoyancy force moves the float 82 vertically upwardly with the float stem member 78 moving out of blocking engagement with the end face 80 by the stem 68.

The water pressure thus acts on the sealing head 66 to force the same into sealing engagement with the valve seating surface 76 to shut off further water in-flow to the dishwasher.

The buoyant force is increased by the annular bell chamber 94 and also may be contributed to by buoyancy of the material itself by employing a molded plastic material of a specific gravity less than 1.

Accordingly, after the water level in the tub 26 approaches the flood level indicated at line 88, the float 82 rises vertically freeing the end of the stem 68 which is thus forced against the annular surface 76, discontinuing further in-flow to the fill hose 44 and the tub 26.

Accordingly, it can be seen that an entirely mechanically operated flood control arrangement is provided which does not require operation of the electrical controls of the dishwasher to thus provide 24-hour protection. The mode of operation with the water pressure creates the valve sealing action acting with a high degree of reliability to prevent flood conditions arising from any cause, either electrical or mechanical of the fill valve assembly 42, or of some other condition, such as a clogged drain.

Once an overfill condition has occurred, the refilling of the tub is precluded by movement of the stem 68 beneath the float stem member 78, such that the owner or operator of the machine is apprised of the fact that there has been a system malfunction creating the flood condition. The machine will therefore be caused to receive proper maintenance attention pior to another use of the dishwasher. The stem 68 is easily repositioned by removal of the hoses 52 and 44, after insuring that the fill valve has functioned to close and repositioning of the sealing plunger 62 has occurred (FIGURE2).

FIGURE 3 depicts an alternate mounting arrangement for the sealing plunger 62 in which a spring 100 is employed to make the repositioning operation simpler, i.e., upon relief of pressure in the inlet chamber 64, the spring 100 will reposition the sealing plunger 62 in the appropriate unsealed position enabling the valve stem member 78 to be repositioned behind the end face 80.

FIGURE 4 depicts an alternate embodiment in which the valving action is controlled by a side engagement of the float stem member 78 with the stem 68. The valve stem member 78 causes the seali#ng plunger 62 to be tilted, thus precluding the sealing engagement of the valve seating surface 74 with the annular surface 76 until such time as the float rises upon the creation of a near flood condition in the tub 26.

Claims (10)

1. A flood control arrangement for preventing flooding of liquid from a container, the arrangement comprising: control valve means interposed in a line supplying liquid to the container, the valve means including a sealing plunger disposed in a housing formed with an inlet chamber for the liquid being supplied to the container, and the head of the plunger being disposed in the inlet chamber such that liquid pressure in the chamber is able to move the head into sealing engagement with a valve seat; a float disposed in the container such that the position of the float is dependent on the level of the liquid in the container; and a blocking member normally blocking movement of the plunger into its sealing position, the blocking member being connected to the float such that the plunger is released for movement only when the liquid in the container reaches a predetermined level.

2. A washing machine comprising an electrically operated solenoid valve, means directing water from the outlet of said electrically operated solenoid valve into a water collecting tub, and a flood control arrangement to prevent overfilling of the tub, the flood control arrangement comprising: flood control valve means interposed in the fluid supply means downstream from the solenoid valve, the flood control valve means including a sealing plunger disposed in a housing formed with an inlet chamber in fluid communication with the outlet of the solenoid valve, the sealing plunger having a head portion disposed in the inlet chamber and movable therein into sealing engagement with a valve seat by water pressure exerted thereon in the inlet chamber; a float disposed in the bottom region of the tub such that the position of the float is dependent on the level of water in the tub, and a blocking member normally blocking movement of the plunger to its sealing position, the blocking member being connected to the float such that the plunger is released for movement into its sealing position when the water in the tub reaches a predetermined level whereby the flood control valve means is activated to preclude further inflow of water to the washing machine upon approach of a flood level condition in the tub.

3. A washing machine according to Claim 2 wherein said blocking member is a float stem member secured to said float and extending downwardly from the tub into the interior atsaid flood control valve housing.

4. A washing machine according to Claim 2 wherein said blocking member consists of a member extending into the flood valve control housing and normally positioned in the path of movement of the sealing plunger.

5. A washing machine according to Claim 4 wherein the plunger housing includes a bore in communication with the inlet chamber, and the sealing plunger has a stem portion extending into the bore and wherein the blocking member extends laterally into the bore to normally block movement of the sealing plunger stem portion.

6. A washing machine according to Claim 2 wherein the plunger includes a stem affixed to its head portion, and wherein the plunger housing includes a bore extending out of said inlet chamber, and wherein the plunger stem extends into the bore with a clearance thereof, and wherein the blocking member extends into the bore and into engagement with a side surface of said plunger stem to tilt the head portion of the plunger to preclude sealing engagement with the valve seat surface and wherein the blocking member is moved away from the plunger stem to enable movement of the plunger into its sealing position only when the water in the tub reaches the predetermined level.

7. A washing machine according to Claim 2 further including a plurality of circumferentially spaced webs extending into engagement with said plunger head, whereby to position said head in said chamber and enabling water flow around said head between the spaces in said circumferentially spaced webs.

8. A washing machine according to Claim 5 further including spring means interposed between said plunger head and the interior of said inlet chamber, the spring means urging said plunger head out of sealing engagement with said valve seat, whereby said plunger may be repositioned upon cessation of the pressure exerted on said plunger head.

9. A washing machine according to Claim 3 further including a float housing substantially enclosing said float, the housing being formed with openings allowing water in said tub to enter said housing.

10. A flood control arrangement according to Claim 1 and substantially as herein described with reference to the accompanying drawings.