GB2226491A

GB2226491A - Tank-flushing assemblies

Info

Publication number: GB2226491A
Application number: GB8927160A
Authority: GB
Inventors: William Alexander Jeffrey
Original assignee: National Research Development Corp UK
Current assignee: National Research Development Corp UK
Priority date: 1988-12-03
Filing date: 1989-12-01
Publication date: 1990-07-04
Anticipated expiration: 2009-12-01
Also published as: GB2226491B; GB8927160D0; GB8828270D0

Abstract

A tank-flushing assembly 50 for use in spray application equipment, comprises one or more 360 DEG dispersion spray heads 10 operative to jet water around the inside top of the tank 54 and to provide a rinsing action down the tank walls. <IMAGE>

Description

TANK-FLUSHING ASSEMBLIES The present invention relates to tank-flushing assemblies and to spray application equipment provided therewith e.g. for use in agriculture, horticulture and forestry.

Hitherto, in order to decontaminate agricultural spray application equipment after use, the spray tank has usually had to be filled to the neck with water to rinse chemical solution from all internal surfaces. The washing procedure has normally had to be repeated several times when changing to a different pesticide. As tractor-mounted sprayers commonly have capacities of 1500 litres or more, the volume of contaminated washings generated can be substantial. Where the washings must be sprayed out, this is wasteful of both the land area required and the operators' time.

An object of the present invention is to provide a tankflushing assembly in which the above problems are significantly reduced.

According to the present invention, a tank-flushing assembly comprises one or more substantially 360e dispersion spray heads operative to jet water or other liquid around the inside of the tank top and to provide a rinsing action down the tank walls.

Conveniently, the or each spray head comprises a multi-plate dispersion nozzle in which a passageway is operative to direct a stream of liquid against successive dispersion plates to provide a corresponding number of spray sheets at different heights in the tank.

Alternatively, or additionally, the or each spray head may comprises a dispersion nozzle in which a passageway is operative to direct a stream of liquid against an obstruction which diverts the liquid outwardly along an appropriate dispersion plate.

Conveniently, where the spray heads are to be used to rinse the tank of spray application equipment, then the spray heads can be plumbed into the equipment's normal pipework in such a way as to be fed from the its spray pump.

Specific embodiments of the present invention are intended for use in flushing the spray tanks of agricultural spray application equipment and liquid storage equipment such as bulk milk tanks, for example. These spray heads may either be fitted as part of the original equipment or they may be supplied in kit form for retro-fitting to existing equipment of this type.

The invention also includes spray application equipment or liquid storage equipment provided with tank flushing assemblies in accordance with the present invention.

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a schematic representation of spray application equipment using multi-plate dispersion nozzles as part of a tank-flushing assembly in accordance with the present invention; Figure 2 shows, on a larger scale, a vertical section of one of the nozzles used in the assembly of Figure 1; and Figure 3 is a part sectional perspective view, also on a larger scale, of an alternative form of nozzle for use in the assembly of Figure 1.

Referring first to Figure 2 of the drawings, this shows the multi-plate dispersion nozzles (10) to comprise two tubular sections 12,13 which are apertured at 15 to direct a stream of water from the central passageway on to the dispersion plates 17,18. These latter spread the water out as two substantially continuous spray sheets which is especially advantageous when the tank top is irregularly shaped, and therefore flushing jets at more than one level are required.

Nozzles marketed by Lumark Ltd. under the title "hydraul'ic mixer" would be suitable for this purpose.

Figure 3 shows an alternative form of dispersion nozzle (20) which comprises a tubular part 22 which is operative to direct a stream of water against a central obstruction 24. This latter diverts the water outwardly along a dispersion plate 26 engaged by the four equally spaced radial feet 28 of the nozzle 20.

Nozzles marketed by Lumark Ltd. under the title "anti-vortex outlet" could be adapted for this purpose by the addition of a suitable restrictor to act as obstruction 24.

There appears to be no inherent reason why the two designs of nozzle above described should not be suitable for use in a wide variety of spray application equipment, either fitted during manufacture or "retro-fitted" to existing equipment. One such use is shown in Figure 1 of the drawings which depicts a tank flushing assembly 50 in accordance with a preferred embodiment of the invention.

Thus referring now to Figure 1, the assembly 50 comprises a spray boom 52, a tank 54 for the liquid (herbicide etc.) to be applied by the spray boom, and a pump 56 for moving liquid from the tank to the spray boom through a suction filter 58, main control valve 60 and delivery filter 62. Reference numeral 64 indicates the usual pressure gauge while reference numeral 66 indicates a conventional by-pass agitator feed with its pressure relief valve 68. The tank 54 is top-loaded through the usual inlet port filter 70.

In order that the tank 54 may be partially filled with water for rinsing purposes (and in accordance with another aspect of the present invention), a rinse recirculation line 72 is tapped off from the usual "spray-off" return line 74 and a suitable two way valve is provided at 76. With valve 76 open, the return line 72 will operate in the usual way, but when valve 76 is closed, liquid which would have returned through the valve direct to the tank 54, is instead redirected via tapping 78 into the rinse recirculation line 72.

At its upper end, the recirculation line is connected via a T-junction 80 and two equal-length hoses 82,83 to two spray heads 10 each conveniently as hereinbefore described with reference to Figure 2 although, as already explained, the nozzles 20 of Figure 3 would also be suitable for this purpose.

Once spraying has been completed and the tank 54 has been emptied of its original contents, water is poured into the tank until it is about one tenth full with water. Then, with valve 76 closed and the main control valve 60 turned to its alternative position (rather than to the valve position illustrated in Figure 1), the pump 56 is used to circulate rinsing water from the tank 54 along line 72 and back through the spray heads 10 as above described. This process is continued until the walls of the tank have been thoroughly rinsed by the spray from spray heads 10. When this has been done, the one way valve 76 is again opened and control valve 60 is returned to its illustrated position to spray out the contaminated washings through the nozzles on spray boom 52.

It will be appreciated that the embodiments of the invention described above will each provide a flushing system which can wash down the inside of the spray tank using only a fraction of the tank's water capacity. By having the one or more 360" dispersion nozzles mounted inside the top of the tank and plumbed into a pressurised part of the sprayer hydraulic circuit, the conventional self fill device (where fitted) may be used to draw clean water through the flush system into the spray tank up to the level where, with the self fill device turned off, the pump does not suck air. Usually, with a typical agricultural sprayer, for example, 50 litres of water will suffice for this purpose.

Thereafter the tank contents are recirculated for as long as is necessary to remove deposits from the tank's inner surfaces before the self fill device is turned on once again to give a final wash down with clean water.

The principal advantage of the present invention over the prior art systems is that significantly less water and time is required than with the conventional fill-and-discharge rinsing technique previously employed.

Although in the illustrated tank-flushing assemblies of the present invention, only two spray heads have been used, it will be appreciated that, in other situations, the assembly may include only a single such spray head or it may include three or more such spray heads, as desired. Whatever the number of spray heads, however, the pump or pumps used should preferably be chosen so as, in most cases, to be able to supply each spray head present with at least 40 litres per minute of the flushing liquid.

It will be appreciated that in accordance with the normal canons of interpretation, the invention extends to the new tank flushing assembly when provided in kit form e.g. for retrofitting in existing equipment.

Claims

1. A tank-flushing assembly comprises one or more 360" dispersion spray heads operative to jet water or other liquid around the inside of the tank top and to provide a rinsing action down the tank walls.

2. An assembly as claimed in Claim 1 in which the or each spray head comprises a multi-plate dispersion nozzle in which a passageway is operative to direct a stream of liquid against successive dispersion plates to provide a corresponding number of spray sheets at different heights in the tank.

3. An assembly as claimed in Claim 1 or Claim 2 in which the or each spray head comprises a dispersion nozzle in which a passageway is operative to direct a stream of liquid against an obstruction which diverts the liquid outwardly along an appropriate dispersion plate.

4. An assembly as claimed in any preceding claim which is adapted for use with spray application equipment and in which the spray heads are adapted to be plumbed into the equipment's normal pipework in such a way as to be fed from its spray pump.

5. Spray application equipment or liquid storage equipment provided with a tank-flushing assembly as claimed in any preceding claim.

6. A tank-flushing assembly, spray application equipment or liquid storage equipment substantially as hereinbefore described with reference to, and/or as illustrated in, the accompanying drawings.