Dispensing – With discharge assistant – Motor operated
Patent
1996-10-18
1999-12-28
Weldon, Kevin
Dispensing
With discharge assistant
Motor operated
B67D 564
Patent
active
060069538
DESCRIPTION:
BRIEF SUMMARY
The invention comprises an apparatus or a device for delivering a preset quantity of fluid.
BACKGROUND
In forestry or horticulture it is often required to deliver a preset quantity of fluid such as liquid herbicide or liquid fertiliser from a sprayer. In forestry or farm forestry for example, herbicide is spot sprayed to cover typically 1m.sup.2 of surrounding ground prior to planting a seedling, or alternatively once a seedling has been planted a shot of selective herbicide is sprayed over the seedling and surrounding ground after planting. A forestry worker may spray a large number of seedlings over the course of a day. It is necessary that a constant amount of herbicide is sprayed around each seedling. Herbicides are expensive and it is also potentially hazardous to use more than is required, but at the same time it is essential that enough herbicide is sprayed around each seedling to do the job. In horticulture it is also often necessary to deliver preset quantities of herbicides, or alternatively liquid fertiliser or the like on or around plants. Again, manually operated back sprayers are often used.
A back pack sprayer typically consists of a tank for the herbicide or fertilizer to be sprayed, which is carried on the back of the operator like a pack. There is also an outlet hose from the tank and a delivery gun used by the operator which is usually trigger operated. There is also a handle which the operator pumps to pressurise the sprayer so that when the operator pulls the trigger of the spray gun the fluid will be delivered as a spray. Delivering a constant quantity of the herbicide or fertiliser requires that the operator maintains a constant pressure and holds the trigger open for a constant period in each operation, which is obviously only a rough estimation.
In another type of sprayer, instead of the spray tank being pressurised the hand held spray gun is based on a modified drench gun and has a pump-action trigger which when squeezed causes spray to be ejected. The squeezing action on each operation pumps the spray, so that when the device is used repeatedly the operators hand quickly becomes tired.
Back pack sprayers incorporating an electric solenoid valve and battery are known. The electric solenoid delivers a constant quantity of spray on each operation, but these sprayers require a power source to operate and are dependent on battery life.
SUMMARY OF INVENTION
The invention provides an improved or at least alternative apparatus for delivering constant quantities of fluid.
In broad terms a first form of the invention comprises apparatus for delivering constant quantities of fluid, comprising a chamber, a piston reciprocally movable within the chamber, a fluid inlet to the chamber on one side of the piston, a fluid outlet from the chamber on the other side of the piston, a valve through the piston including a valve stem extending through the outlet side of the chamber to the fluid outlet, and spring means and subsidiary spring means urging respectively the piston and valve through the piston towards the inlet side of the chamber, such that fluid pressure on the inlet side of the chamber will cause the piston to move to eject a predetermined quantity of fluid from the outlet side and on the return stroke fluid will flow through the valve in the piston to refill the outlet side for the subsequent piston delivery stroke.
DESCRIPTION OF DRAWINGS
Two preferred forms of the apparatus of the invention are illustrated in the accompanying drawings, by way of example and without intending to be limiting. In the drawings:
FIG. 1 shows a first preferred form of the device at rest i.e. with no fluid pressure on the inlet side of the device,
FIG. 2 shows the first preferred form of the device part way through a delivery stroke,
FIG. 3 shows the first preferred form of the device at the end of the delivery stroke,
FIG. 4 shows the first preferred form of the device part way through the return stroke, and
FIG. 5 shows a second preferred form of the device part way through the delivery stroke.
DE
REFERENCES:
patent: 1896036 (1933-01-01), Bell
patent: 2142973 (1939-01-01), Draper
patent: 3292867 (1966-12-01), Hunter
patent: 4157773 (1979-06-01), Schetina et al.
patent: 4222358 (1980-09-01), Hofbauer
patent: 4438872 (1984-03-01), Dooley et al.
patent: 4485971 (1984-12-01), Pajevic
patent: 5398873 (1995-03-01), Johnson et al.
Bowden Dean Mark
Newson Richard John
Vigil Thomas R.
Weldon Kevin
LandOfFree
Preset quantity fluid delivery apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Preset quantity fluid delivery apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Preset quantity fluid delivery apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2376766