GB2136319A - Spraying equipment - Google Patents

Abstract

Spraying equipment, for example for spraying herbicide, comprises a tubular support member (2) having a spraying head (6) at one end and a handle (12) at the other. A supply duct (38) and an electrical lead (36) extend through the interior of the support member (2) to supply fluid and electrical power to a rotary atomising disc (54) and a motor for driving the disc. The supply duct (38) communicates through the handle (12) with a container of the fluid, and the lead (36) is connected to a battery (10). <IMAGE>

Description

SPECIFICATION Spraying equipment This invention relates to spraying equipment, particuiarly, although not exclusively, equipment for spraying herbicides.

According to a first aspect of the present invention, there is provided spraying equipment comprising a spraying head mounted on one end of an elongate support member, the spraying head comprising a rotary atomising disc and an electric motor for driving the disc in rotation, the equipment further comprising an electrical lead connected to the motor and a fluid supply duct for supplying fluid to the atomising disc, the electrical lead and the supply duct extending within the support member and being provided at the end of the support member away from the head with means for connection to, respectively, a source of electrical power and a container of fluid to be sprayed.

In a preferred embodiment, the support tube is mounted on a bracket which is adapted to be connected to a battery constituting the source of electrical power. The bracket also includes a handle so that the equipment can be carried and operated by hand. The bracket may be provided with a manually operated valve controlling the supply of liquid to the spraying head and an on/off switch for controlling the supply of electrical power to the spraying head. The bracket may also be provided with an adjustable voltage regulator so that the voltage at the electric motor, and consequently the speed of rotation of the atomising disc, can be varied. This variability enables the spraying width of the equipment and the size of the droplets issuing from the atomising disc to be varied.

The spraying head may comprise a housing provided with a plurality of restrictor passages having different flow cross-sectional areas from each other, each passage opening at one end adjacent the atomising disc and at the other end into a socket for receiving an end of the liquid supply duct.

Consequently, the flow rate of liquid to the atomising disc can be varied by fitting the liquid supply duct into the appropriate one of the sockets. The restrictor passages are preferably provided in jets which are removably fitted in the housing. There may, for example, be three such jets, the passages of which have diameters of, for example, 0.7 mm, 1 mm and 1.5 mm. The supply duct may comprise a flexible tube having an end fitting for insertion into the sockets.

For a better understanding of the present invention, and to show how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a perspective view of spraying equipment; Figure 2 is a partly sectioned view taken along the line Il-Il in Figure 1; Figure 3 is a partly sectioned view taken along the line Ill-Ill in Figure 1; and Figure 4 is a partial end view taken in the direction of the arrow IV in Figure 3.

Referring to Figure 1, the spraying equipment comprises a support tube 2 which is connected at one end to a supply assembly 4 and carries at the other end a spraying head 6. The supply assembly 4 comprises a battery carrier 8 to which a battery 10 is connected and which is provided with a hollow handle 12. The handle 12 is mounted between front and rear limbs 14 and 1 6 of the battery carrier 8 and is connected at its rear end to a fluid supply line 1 8. Near its front end, the handle 12 is provided with an on/off tap 20, and at its extreme end it is connected to the support tube 2 by a fitting 22.The interior of the handle 12 thus provides an intermediate duct, a supply tube 38 communicating with this intermediate duct and consequently with the fluid supply line 1 8. As can be seen from Figure 2, the supply tube 38 is provided at its end with a flanged connector 40.

An O-ring 42 is compressed between the connector 40 and a shoulder provided on the handle 12 under the action of the fitting 22.

The battery 10 is connected to the bracket 8 by terminal nuts 24 (only one of which is visible in Figure 1). The two terminals are connected by a lead 26 to an adjustable voltage regulator 28 controlled by a knob 30. The output of the voltage regulator 28 is connected by a short lead 32 to an on/off switch 34. The on/off switch 34 is connected by a further lead 36 to the spraying head 6. The electrical circuitry is disclosed in greater detail in my co-pending patent application No. 8305003 (Serial No. 2131327).

As will be appreciated from Figures 1 and 2, both the lead 36 and the supply tube 38 extend down the support tube 2. The lead 36 extends through an opening 44 in the front limb 14 of the bracket 8 and through an opening 46 in the support tube 2.

As shown in Figure 3, the spraying head 6 comprises a body 48 which accommodates an electric motor 50 having an output spindle 52.

The lead 36 is connected to the input terminals of the motor 50. The output spindle 52 of the motor carries a rotary atomiser disc 54, the spindle 52 being a friction fit within a bore 56 in the disc 54.

The body 48 has three angularly spaced passages 58. Each of these passages is inclined to the axis of the motor 50 such that it extends inwardly and towards the atomising disc 54. At the inner end of each passage 58 there is a jet 60 having a restrictor passage 62. The diameters of the restrictor passages 62 of the jets are different from one another. The restrictor passages 62 open into a cavity 64 in the end of the body 48. The cavity is defined by a circumferential wall which terminates at a lip 66 defining, with the disc 54, an annular outlet slot 68.

The radially outer portion of each passage 58 constitutes a socket for receiving an end fitting 70 of the supply tube 38.

In use of the equipment, the fluid supply line 18 is connected to a container in a manner described in more detail in my co-pending patent application No.8305003 (Serial No. 2131327). The bracket 8 is connected to the battery 10 by nuts 24. The control rocker of the tap 20 is depressed to allow liquid, such as herbicide, from the container to descend under the action of gravity through the handle 1 2 and the supply tube 38 to the spraying head 6, where it passes through the end fitting 70 and the restrictor passage 62 into the cavity 64.

The switch 34 is turned to the "on" position which causes power to be supplied from the battery 10 to the motor 50 to spin the atomiser disc 54. The liquid flows as an annular stream through the aperture 68 and is ejected by centrifugal force from the atomising disc 54 over the entire periphery of the atomiser disc. The width of the annular gap 68 is carefully selected, in dependence of the viscosity of the liquid to be sprayed, so as to ensure that an even distribution of the liquid reaches the rotary atomiser disc to achieve all-round spraying.

By controlling the voltage applied to the motor 50 by means of the voltage regulator 28, the speed or rotation of the atomiser disc 54 can be adjusted. Such adjustment will vary not only the distance over which the liquid is ejected from the disc 54, but also the size of the droplets into which the liquid is broken up as it leaves the atomising disc 54. Thus, the higher the speed of rotation, the greater the spreading width and the smaller the droplet size. In the embodiment illustrated, the speed of rotation of the atomising disc 54 is variable between approximately 200 and 4000 rpm. The disc 54 shown fitted to the output shaft 52 has a diameter of approximately 20 mm and will, at low speed, spray the liquid over a circular area having a diameter of approximately 10 cms with a large droplet size.

Increasing the speed reduces the size of the droplets but will increase the diameter of the sprayed area to approximately 60 cms.

In order to achieve both a desired droplet size and a desired spreading width, the atomizing disc 54 may be replaced by alternative discs 54' and 54", illustrated in Figure 3. The disc 54' has a diameter of approximately 30 mm and, at low speed, will spray over a circular area of approximately 30 cms diameter with large droples and, at high speed, an area of approximately 1.2 metres diameter with small droplets. The smaller disc 54" has a diameter of approximately 10 mm, and at low speeds, will spray over an area of approximately 5 cms diameter with large droplets and an area of approximately 45 cms diameter with finer droplets, although the variation of droplet sizes at all spraying widths is likely to occur with the smaller disc.

The discs are a simple push fit on the output shaft 52 of the motor 50. However, in order to withdraw a disc from the output shaft 52 without damaging the periphery of the disc, a suitable tool may be provided for insertion into the passage 56.

For example, the tool may comprise a screw threaded shank and the passage 56, at least at the end away from the output shaft 52, may be tapped to receive the shank.

Adjustment of the flow rate of liquid to the cavity 64 and thus from the disc 54 may be achieved by inserting the fitting 70 into the appropriate socket 58, since the flow rate will be controlled by the diameter of the restrictor passage 62 in the jet 60. These passages may, for example, range from 0.75 mm to 2 mm.

The spraying equipment described with reference to the drawings provides simple adjustment of spraying width and droplet size to meet the requirements of different circumstances.

For example, in windy conditions, it is desirable to have a large droplet size in order to avoid wind drift.

Although the present invention has been described with reference to the spraying of herbicides, it is also suitable for other spraying operations, such as the spraying of lubricants or coating compositions such as varnish.

Claims (14)

1. Spraying equipment comprising a spraying head mounted on one end of an elongate support member, the spraying head comprising a rotary atomising disc and an electric motor for driving the disc in rotation, the equipment further comprising an electrical lead connected to the motor and a fluid supply duct for supplying fluid to the atomising disc, the electrical lead and the supply duct extending within the support member and being provided at the end of the support member away from the head with means for connection to, respectively, a source of electrical power and a container of fluid to be sprayed.

2. Spraying equipment as claimed in claim 1, in which the support member is tubular, and in which the supply duct comprises a supply tube which extends within the interior of the support member.

3. Spraying equipment as claimed in claim 2, in which the electrical lead extends within the interior of the support member.

4. Spraying equipment as claimed in any one of the preceding claims, in which the support member is provided, at its end away from the head, with a handle through which extends an intermediate duct which communicates with the supply duct, the handle being provided with means for connecting the intermediate duct to a container of fluid to be sprayed whereby, in use, fluid passes from the container and through the intermediate duct in the handle and the supply duct to the head.

5. Spraying equipment as claimed in claim 4, iri which the support member is releasably connected to the handle, sealing means being provided between oppositely disposed faces of the handle and the supply duct.

6. Spraying equipment as claimed in claim 5, in which the oppositely disposed faces comprise a shoulder provided within the handle and a face of a flanged connector provided at the adjacent end of the supply duct.

7. Spraying equipment as claimed in claim 6, in which the sealing means comprises an O-ring.

8. Spraying equipment as claimed in any one of claims 4 to 7, in which the handle is provided with a valve for controlling the supply of fluid to the supply duct.

9. Spraying equipment as claimed in any one of claims 4 to 8, in which the handle is elongate, the support member being provided at one end and the connecting means being provided at the other end.

10. Spraying equipment as claimed in any one of claims 4 to 9, in which the connecting means comprises a flexible tube connected at one end to the handle and provided at the other end with a connector for connection to a container of fluid.

11. Spraying equipment as claimed in any one of claims 4 to 10, in which the handle is provided with a bracket for supporting a battery constituting the source of electrical power.

12. Spraying equipment as claimed in claim 11, in which the electrical lead emerges from the support member adjacent its end away from the head for connection to the battery.

13. Spraying equipment as claimed in claim 11 or 12, in which the bracket is provided with control means for controlling the supply of current to the motor.

14. Spraying equipment as claimed in claim 13, in which the control means comprises a voltage regulator whereby the speed of the motor is controllable.

1 5. Spraying equipment as claimed in any one of the preceding claims, in which the head has a plurality of sockets, each of which contains a respective metering jet for metering the flow of fluid to the disc, the metering jets having different sizes from each other and the supply duct terminating in a flexible portion having an end fitting for insertion into any selected one of the sockets.

1 6. Spraying equipment as claimed in claim 15, in which the flexible portion emerges from the support member adjacent the head and extends externally of the head to the socket.

1 7. Spraying equipment substantially as described herein with reference to, and as shown in, the accompanying drawings.