GB2201085A

GB2201085A - Nozzle arrangement in dishwashing machine

Info

Publication number: GB2201085A
Application number: GB08803420A
Authority: GB
Inventors: Ugo Favret; Giovanni Centis; Antonio Martegani
Original assignee: Industrie Zanussi SpA
Current assignee: Industrie Zanussi SpA
Priority date: 1987-02-18
Filing date: 1988-02-15
Publication date: 1988-08-24
Anticipated expiration: 2008-02-15
Also published as: FR2610816B3; IT8734014V0; ES1004594Y; GB8803420D0; IT211722Z2; FR2610816A3; DE8801390U1; ES1004594U; GB2201085B

Abstract

A nozzle 13 for supplying recirculated water from wash tank 4 of a dishwashing machine via pump 8, water supply conduit 5, and a free air space to a spray arm 11 rotatably mounted on crockery basket 7 is arranged at a location spaced from the end of the water supply conduit at a right angle thereto and so as to extend within the conduit for at least half its own axial length. The enclosed portion 14 of the nozzle, which may have a converging bore, may be provided with fins 17 for flow regulating purposes. Reduction in the projecting length of the nozzle avoids obstruction when moving the crockery basket loaded with dishes. <IMAGE>

Description

HYDRAULIC CIRCUIT FOR DISHWASHING MACHINE, The present invention relates to a hydraulic circuit for a dishwashing machine, in particular of the type described in patent IT-A-1 050 958.

Such a dishwashing machine comprises within the washing tank a lower hydraulic arm arrangement and an upper hydraulic arm arrangement which are supplied by a circulating pump by way of respective rotary hydraulic joints. In particular the upper arm arrangement is rotatably supported by an associated crockery supporting basket and is connected to the circulating pump by way of a hydraulic conduit which is external to the tank; that conduit passes into the i-nterior of the tank at the roof thereof by means of a relatively long nozzle which is capable of supplying the rotary joint of the upper arm arrangement across a free air space.

The nozzle is necessary for ensuring adequate characteristics in respect of alignment, velocity and pressure of the jet of water which supplies the upper arm arrangement, but it constitutes a physical obstacle which restricts the arrangement of the crockery in the upper basket in order to avoid collisions between the dishes themselves and the nozzle during movement of pulling out and pushing in the support basket.

It would be desirable, and this is the aim of the invention, to provide a hydraulic circuit for a dishwashing machine of the above-indicated type, which affords optimum functioning by minimising the problems relating to the size of the nozzle for supplying the upper rotary arm.

According to the present invention, there is provided a hydraulic circuit for a dishwashing machine comprising a washing tank, in the upper part of which a hydraulic arm is rotatably supported by a crockery-supporting basket, the arm being capable of being supplied via a free air space by a nozzle disposed at the roof of the tank and connected to a pump for circulating the water by way of a supply conduit, in which the nozzle branches off in a substantially orthogonal direction with respect to the terminal portion of the supply conduit, at a location spaced from the end thereof, and in part extends into and is surrounded by the interior of that conduit portion, for at least half of its own axial length.

The invention will be further described by way of nonlimiting example with reference to the accompanying drawings in which: Figure 1 is a diagrammatic view in section of a dishwashing machine provided with the hydraulic circuit according to the invention, and Figure 2 is a view in section of a detail from figure 1 on an enlarged scale.

Referring to figure 1, the dishwashing machine primarily comprises a casing 3 and a washing tank 4 in which are disposed a lower basket 6 and an upperbasket 7 for supporting the articles to be washed. Disposed below the baskets 6 and 7 are associated rotary spray arms 9 and 11 which are supplied by a pump 8 for circulating the water which is collected at the bottom of the tank. I particular the discharge of the pump 8 is connected directly to the arm 9 by way of a rotary hydraulic joint 20 while it is connected to the upper arm 11 by way of a supply conduit 5 which extends upwardly to the roof of the tank 4 and along the space between the tank 4 and the casing 3.

The conduit 5 passes into the interior of the washing tank with a nozzle 13 which supplies the arm 11 by way of a free air gap and a rotary hydraulic joint 10.

Preferably the rotary joints 10 and 14 and the system for supporting the rotary arm 11 on the basket 7 are as described in Italian patent IT-A-1050958.

With reference also to figure 2, the terminal portion 12 of the supply conduit 5 is of a box-like configuration to prevent the formation of rotational movements in the fluid which is directed towards the nozzle 3, as has also been experimentally verified; the nozzle 13 extends from the conduit portion 12 with the axis substantially orthogonal.

and disposed at a certain distance from the end 19 of the conduit 5. In particular, the nozzle 13 extends into the interior of the terminal portion 12 for about half of its overall axial length, that is, over the entire length of a first axial portion 14 which is of a convergent shape and which is connected to a substantially cylindrical axial portion 15 extending into the tank 4. The axial lengths of the convergent and cylindrical portions are substantially equal to the inner diameter of the cylindrical portion.

As has also been experimentally verified, the nozzle 13 can effectively produce an optimum jet of water if the diameter of the cylindrical section 15 is about equal to its axial length while the diameter of the inlet mouth 16 of the nozzle 13 is about equal to two thirds of the axial length of the nozzle.

The thickness of the terminal portion 12 is preferably of similar measurements, which it is considered in the direction of the axis of the nozzle 13.

That means that the inlet mouth 16 of the nozzle 13 is relatively adjacent to the top wall of the terminal portion 12 but that not only does not impede but stabilises the flow of water toward the nozzle 13, which is of the 'peripheral' type, by virtue of the fact that the plan of the conduit portion 12 of the box-like shape is sufficiently wide with respect to the entry mouth 16 of the nozzle 13.

As will be apparent from the foregoing description, the nozzle 13 can extend-into the interior of the washing tank for an extremely limited distance (for example 7 mm), thus avoiding any problem in regard to size and/or collision with the crockery, without thereby affecting the effectiveness of the jet of water which supplies the rotary joint 10 and thus the arm 11.

It will be appreciated that the hydraulic circuit may be the subject of many modifications which fall within the scope of the invention. For example, at least the convergent portion 14 of the nozzle 13 may be provided with axial fins 17 to produce a lamination effect in respect of the flow of water.

In addition the nozzle 13 is preferably produced integrally with a ring nut 18 which is shaped as shown in figure 2 and which is screwthreaded to be screwed at least indirectly on to the conduit portion 12 with the interposition of the wall of the tank 4 and suitable seals.

Claims

1. A hydraulic circuit for a dishwashing machine comprising a washing tank, in the upper part of which a hydraulic arm is rotatably supported by a crockerysupporting basket, the arm being capable of being supplied via a free air space by a-nozzle disposed at the roof of the tank and connected to a pump for circulating the water by way of a supply conduit, in which the nozzle branches off in a substantially orthogonal direction with respect to the terminal portion of the supply conduit, at a location spaced from the end thereof, and in part extends into and is surrounded by the interior of that conduit portion, for at least half of its own axial length.

2. A hydraulic circuit according to claim 1 wherein the nozzle has a convergent re-entrant portion and a substantially cylindrical portion, the axial lengths of the convergent and cylindrical portions being substantially equal to each other and to the inner diameter of the cylindrical portion.

3. A hydraulic circuit according to claim 1 or 2 wherein said terminal portion of the supply conduit is of a substantially box-like shape and is of a thickness, considered in the axial direction of the nozzle, which is substantially equal to the diameter of the entry mouth and to two thirds of the axial length of the nozzle.

4. A hydraulic circuit according to claim 2 or claim 3 when appendant thereto wherein at least the convergent portion of the nozzle is provided with axial flow-lamination vanes.

5. A hydraulic circuit constructed and arranged to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

6. A dishwashing machine incorporating a hydraulic circuit according to any one of the preceding claims.