GB2306900A - Improved spray device - Google Patents

Abstract

Material to be sprayed is pumped upwardly through a delivery pipe 2 to the upwardly facing concave surface of a disc 1. The disc 1 is rotated by being connected to and rotating with an armature 5. Magnets 14 on the armature are driven by the electrical windings 15 of a DC motor. The pipe 2 is rigidly attached to the rearward portion 5 to a casing 3 at a lower end 9 thereof.

Description

IMPROVED SPRAY DEVICE The present invention relates to spray devices and spraying systems, and is particularly although not exclusively concerned with spraying a flowable or fluid material such as various glazes, oil, slurry, sugar, syrup, water, emulsion and other materials with or without particles in suspension in the bakery, confectionary, snack food, frozen food, meat and savoury pie production and other food processing industries.

One type of prior art spray apparatus for spraying a flowable or fluid material onto food articles passing along a conveyor, comprises a conveyor for conveying the food articles in a substantially horizontal plane, and a spray gantry, which fits over the conveyor, for spraying the material onto the moving food articles. The spray gantry comprises a cabinet enclosure having a plurality of prior art spray devices. The gantry is mounted on a trolley which is capable of being wheeled underneath the conveyor, such that the overhead spray gantry lies over the conveyor belt.

A first pair of spray devices are positioned above the conveyor facing upstream of the conveyor, and oppositely to the first pair of spray devices are positioned a second pair of spray devices facing down stream of the conveyor and opposite the first pair of spray devices, the arrangement being that in use, the first and second pairs of spray devices spray the flowable material in a direction downwardly onto the passing food items.

In the prior art spray apparatus, each spray device comprises a spinning disc onto which the material to be sprayed is supplied. The disc spins the material in a spray over the food items. Each spray device is provided with its own separate AC electric motor, arranged adjacent the spray device, and in side by side relationship thereto, the motor driving the spray device via a belt and pulley drive. If one electric motor fails, the other three spray devices will still operate, and thus the food item production line can be kept running, albeit with the food items having a reduced thickness coating of the material.

However, as each of the motors is relatively heavy, weighing around 3kgs, and as each prior art spray device weighs around 0.5kegs, when the spray devices are in operation there is a limit to the width of conveyor which can be accommodated with the gantry system, without producing a heavy and unwieldy gantry trolley to support the motors and spray devices.

In a second prior art design of spray apparatus, there is provided a gantry having two spray devices, in side by side relationship. Due to space considerations, each spray device, comprising a spinning disc, is mounted axially in line with the rotor of a respective AC electric motor, such that each disc rotates with an axis facing inclined at an angle upwardly. The material to be sprayed is introduced onto the disc from a position opposite a concave front face of the disc via a material delivery pipe placed oppositely the front face of the disc and spaced apart therefrom. As the disc faces upwardly, inclined to the horizontal, the material delivery pipe has an outlet which faces downwardly towards the disc.

However, whilst the arrangement of a spray device mounted in line with an AC motor is compact, there is still the weight problem of the external motor, and there is a problem of controlling the flow of material onto the disc, which tends to drop out of the downwardly directed material delivery pipe.

In both the prior art spray devices, for servicing of the spray devices they must be detached from the drive motor by the user, which poses an electrical safety risk in a wet environment, and can pose a contamination risk for motor or spray device lubricants contaminating food product.

Specific embodiments of the present invention aim to provide an improved spray device.

According to one aspect of the present invention there is provided a spray device comprising: a disc having a front face, arranged to spray a material; a motor directly connected to the disc, for driving the disc in a rotational movement; and a material delivery pipe, the material delivery pipe arranged to supply the material to the front face of the disc, through an aperture in the disc, from a position behind the front face of the disc.

Preferably, the motor is mounted substantially along a line of a main rotational axis of the disc.

In embodiments of the present invention by incorporating a DC motor in line with the main rotational axis of the disc, an advantage of achieving a compact integral spray device unit may be achieved, which can be replaced as a complete unit, as compared with the prior art external motor plus spray device, where the motor needs to be detached from the spray device for servicing or repair of the spray device or motor.

Preferably, a main rotational axis of the motor substantially coincides with a main rotational axis of the disc.

A problem of size and weight may be reduced as compared to the prior art side by side motor driven spray device having a separate motor driving a prior spray device, in a side by side relationship via a pulley.

Preferably, said motor and said material delivery pipe are arranged on another side of the disc opposite to the side of the disc from which the material is arranged to be sprayed.

By arranging the motor in line with a main central axis of the disc, and by providing the material delivery pipe on the same side of the disc as the motor, the delivery pipe may be arranged to face upwardly when the spray device is mounted in a spray apparatus such that the concave face of the disc faces upwardly, with the advantage that as the material delivered is pumped against gravity, the rate of the flow of the material delivered to the disc may be more accurately controlled as compared to the prior art in-line motor type in which the delivery tube opens in a downward direction. At the same time, as the motor is positioned directly in line with the disc, a compact arrangement of spray device can be achieved.

Thus, a problem of control of flow rate in the delivery pipe of the prior art in-line type spray device may be solved.

Ideally the motor is connected directly to another side of the disc to the side of the disc which sprays the material.

Preferably, the motor comprises an electric motor having an outer casing and an inner armature, wherein said disc is mounted directly to said armature.

Preferably, the material delivery pipe passes substantially along a central axis of the armature.

Preferably, said armature revolves around said material delivery pipe.

Since the delivery pipe is coincident with the armature of the motor, the delivery pipe plus motor may comprise an integral spray device having a smooth sealed outer surface which can easily be cleaned of dirt, excess material etc., which is particularly useful in the food industry, where residual dirt may harbour harmful bacteria, if not cleaned.

Preferably, said armature rotates within said casing via a set of bearings, the arrangement being that said armature is concentric within said casing and revolving therein.

Preferably, said material delivery pipe is rotationally fixed with respect to said casing, and concentric therewithin, said armature arranged to rotate between said casing and said material delivery pipe.

Suitably said armature extends in a direction of a main rotational axis of said armature either side of a first set of bearings, said disc being positioned on one side of said bearings, and a set of electrical windings being positioned on another, opposite side of said bearings.

The invention includes a spray apparatus comprising an overhead gantry containing one or a plurality of spray devices according to the above aspects.

The spray devices are preferably arranged in the gantry such that discs face upwardly, so that the material can be delivered to the material spray side of the disc, against the force of gravity.

For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings, in which: Figure 1 shows in cut away view, a spray device according to a first specific embodiment of the present invention; Figure 2 shows a rear view of a spray apparatus for spraying articles on a conveyor line, in accordance with a second specific embodiment of the present invention; and Figure 3 shows in side view the spray apparatus of figure 2.

Referring to figure 1 of the accompanying drawings, a spray device comprises a concave disc 1 for receiving a material to be sprayed, and spraying the material at high rotational speed from the outwardly facing concave surface of the disc; a material delivery pipe 2 extending from a position behind the disc, ie. another side of the disc opposite to the concave side, to deliver a material to be sprayed through an aperture in the disc, and onto the concave surface of the disc; a casing 3, the casing comprising a forward section 4 into which are mounted first and second sets of roller bearings 6, 7 respectively, and a rearward section 8 encasing a set of motor windings 15, there being a central armature 5 lying concentrically with the casing, and rotating therewithin via the first and second sets of roller bearings 6, 7 respectively. The central armature 5 is tubular.Through a substantially cylindrical central passage of the armature passes the material delivery pipe 2, which is rigidly attached to the rearward portion 5 of the casing at a lower end 9 thereof. The disc 1 is directly attached to a forward end of the armature via a plurality of screws 10, the forward end of the armature being movably sealed with the forward section 4 of the casing 3 by a labyrinth seal 11 which prevents the ingress of dirt to the casing and prevents the exit of motor lubricants from the casing.

A rearward portion 12 of the armature is provided with a set of permanent magnets 14, the magnets being arranged in a substantially cylindrical fashion around the central armature and passing the set of electrical windings 15, said permanent magnets and said windings 15 comprising a DC motor, suitably of 24V DC.

In use, a peripheral flange 20 of the forward part 4 of the casing 3 may be mounted on a mounting plate 21 of a spray apparatus, securely fixing the casing 3 to the mounting plate 21.

Referring to figures 1 to 3 of the accompanying drawings, suitably when the spray device is in use installed in a spray apparatus, a main rotational axis of the disc, which is coincident with the main rotational axis of the armature 5, is arranged at a position inclined to horizontal, such that the concave surface of the disc 1 faces upwardly, and such that the delivery pipe 2 is arranged with its open end 18 facing in an upward direction.

The armature 5 rotates with respect to the casing 3 and the electrical windings 15 such as to directly drive the disc 1 which is fixed to the armature. The material delivery pipe 2, which suitably does not rotate, delivers to the disc the material to be sprayed, which is pumped against the force of gravity out of the open end of the material delivery pipe 2 and via a conical valve member 22 onto a diffuser plate 23 which directs the material onto the concave surface of the disc 1, from which the material is sprayed outwardly off the outer peripheral edge of the disc due to the high rotational speed of the disc.

Because the material is pumped up the delivery tube against the force of gravity, the material can be smoothly delivered to the rotating disc at a constant rate which is readily controllable by a pumping means down line of the delivery pipe.

The material to be sprayed is delivered to the upwardly facing concave surface of the disc, from which the material is sprayed, deliver of the material being against gravity from a position on the other side of the disc to the side from which the material is sprayed, and on the same side of the disc as the motor, the material being delivered through the motor and through an aperture in the disc. On passing through the aperture in the disc, the material is re-directed from a flow direction substantially axially of the motor and axially of the axis of the rotation of the disc, to a direction radially outwards, by the conical valve member 22, and the diffuser plate 23.

As the delivery pipe runs through a central axis of the casing 3 and armature 5, and as the delivery pipe and motor are integral with each other the disc can be mounted directly to the motor, producing a compact spray device arrangement having disc, delivery pipe and electric motor formed in a sealed unit.

Further, by use of a DC motor, an improvement in disc speed control and disc speed range may be achieved as compared with the prior art spray devices. For example, with a prior art conventional AC motor and conventional spray device, the AC motor has a limited range. For example individual AC motors are available with speed ranges of 700 to 2,800 rpm; 1,400-5,000 rpm; or 350-1,400 rpm, whereas a single DC brushless motor may provide speed in the range 50-10,000 rpm. Thus, instead of providing three alternative prior art motors, to cover a range of speeds 700 to 5,000 rpm, a wider range can be provided by a single unit of the present disclosure.

Further, since a low voltage DC motor of 24 volts may be used, the conventional AC mains voltage motor of 250 or 110 volts can be avoided, enabling a safer, low voltage spray device for use in production line environments, where conductive fluids eg. water may present an electrical shock hazard.

By use of a DC motor directly connected to a spray disc, with a delivery pipe passing centrally through the motor, a weight reduction may be achieved compared with the prior art devices.

For example, for the conventional AC motor and conventional spray device the weight of the AC motor is around 3kg and the weight of the prior art spray device is around 500g. For the present specific embodiment, of equal performance to the prior art arrangement, the overall weight may be of the order of 1keg.

Due to the reduced weight of the present specific embodiment, a plurality of the spray devices may be arranged in line in an overhead spray apparatus gantry, enabling either a higher number of spray devices for a given cantilever distance, enabling more uniform spray coverage, or enabling a longer cantilever gantry overhang with a greater number of spray devices, for a given weight.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims (14)

1. A spray device comprising: a disc having front face, arranged to spray a material; a motor directly connected to the disc, for driving the disc in a rotational movement; and a material delivery pipe, the material delivery pipe being arranged to supply the material to the front face of the disc, through an aperture in the disc, from a position behind the front face of the disc.

2. A spray device according to claim 1, in which the motor is mounted substantially along a line of a main rotational axis of the disc.

3. A spray device according to claim 1 or 2, in which a main rotational axis of the motor substantially coincides with a main rotational axis of the disc.

4. A spray device according to any one of the preceding claims, in which said motor and said material delivery pipe are arranged on a side of the disc opposite to the side of the disc from which the material is arranged to be sprayed.

5. A spray device according to any one of the preceding claims, in which the motor comprises an electric motor having an outer casing and an inner armature, wherein said disc is mounted directly to said armature.

6. A spray device according to claim 5, wherein said material delivery pipe passes substantially along a central axis of the armature.

7. A spray device according to claim 5 or 6, in which said armature revolves around said material delivery pipe.

8. A spray device according to any one of claims 5 to 7, wherein said armature rotates within said casing via a set of bearings, the arrangement being that said armature is concentric within said casing and revolving therein.

9. A spray device according to any one of claims 5 to 8, wherein said material delivery pipe is rotationally fixed with respect to said casing, and concentric therewithin, said armature arranged to rotate between said casing and said material delivery pipe.

10. A spray device according to any one of claims 5 to 9, wherein said armature extends in a direction of a main rotational axis of said armature either side of a first set of bearings, said disc being positioned on one side of said bearings, and a set of electrical windings being positioned on another, opposite side of said bearings.

11. A spray device according to any one of the preceding claims, wherein said motor comprises a DC electric motor.

12. A spray device in which the delivery pipe and the front face of the disc are arranged to face upwardly.

13. A spray device substantially as herein described with reference to and as shown in any of figures 1 to 3 of the accompanying drawings.

14. A spray apparatus comprising an overhead gantry containing one or a plurality of spray devices according to any one of the preceding claims.