GB2093327A

GB2093327A - High pressure liquid cutting means

Info

Publication number: GB2093327A
Application number: GB8204059A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-02-21
Filing date: 1982-02-11
Publication date: 1982-09-02

Abstract

High pressure liquid cutting means primarily for cutting grass is provided in which a fine bore nozzle (1) receives water (or other liquid) at high pressure from a pump (2), the high pressure cutting jet (W) of water issuing from the nozzle (1) being received by the orifice (11) of a collector member (10) aligned with the nozzle (1). Water received by the collector (10) is returned to a reservoir (4) for re-circulation by the pump (2) to the nozzle (1) so that a small quantity of water can be repeatedly used for a prolonged period. Multiple or ganged arrangements of nozzles (1) and corresponding collector members (10) may be employed for obtaining a required cutting width or swathe, e.g. in conjunction with a finger bar. <IMAGE>

Description

SPECIFICATION High pressure liquid cutting means This invention relates to cutting means in which a jet or jets of liquid such as water at high pressure is or are employed to cut through material of various kinds.

The object of this invention is to provide an improved arrangement of such cutting means particularly, but not exclusively, suited for cutting grass or for similar purposes herein referred to.

Practical advantages of the invention will be apparent from the following disclosure.

According to this invention high pressure liquid cutting means is characterised by at least one nozzle for the discharge of a jet of water or other liquid at high pressure for cutting purposes, the nozzle being aligned with an inlet orifice of a collector member spaced therefrom for receiving the jet of water or other liquid in order to substantially recover the latter, e.g. for recirculation to the nozzle.

In practice and for grass cutting or similar purposes, the construction and arrangement is as shown in the accompanying drawings in which: FIGURE 1 is a diagram of the cutting means and associated water supply system, FIGURES 2 and 3 are diagrams of multiple jet arrangements, and FIGURES 4 and 5 are diagrammatic plan views showing multiple jet arrangements in relation to a mowing machine finger bar.

Referring to FIGURE 1 a fine bore nozzle 1 having an outlet of hard wear resistant material is supplied with water (or other suitable liquid) at high pressure from a pump 2, the pressure being of the order of 10,000 to 20,000 p.s.i. (700 to 1400 kg/cm2) or more. By means of support structure 12 the nozzle 1 is accurately aligned with an inlet orifice 11 of a collector or pick up member 10 spaced therefrom whereby a jet W issuing from the nozzle 1 is received by the orifice 11 for recovery of a major part of the water which would otherwise be lost. As shown in FIGURE 1 the water recovered at 10 is passed by pipework 3 to a reservoir 4 for re-circulation from the latter back to the nozzle 1 by the pump 2, filters being preferably provided at 5 and 6.

Thus the supply of water is conserved with only a gradual working loss due to the cutting action of the jet W so that a small quantity of water can be used in the supply system for a prolonged period.

The cutting means is thus particularly suited for mobile use in grass cutting such as of grass verges and can be of compact form for carrying by an agricultural tractor or other suitable vehicle" that part of the cutting means including the nozzle 1 and the collector member 10 being incorporated in a cutting head indicated at 100 and in turn carried by an arm or boom (not shown) extending from the tractor with suitable flexible hose connection, the cutting head 100 thus taking the place of a conventional mechanical cutter of the rotary or reciprocating blade type.

However, in contrast to a mechanical cutter, the cutting means according to this invention is not prone to damage otherwise caused by hard objects such as stones, roots or the like from which the jet W is simply deflected with a small loss of water.

The nozzle 1 should be accurately aligned with the inlet orifice 11 in the collector member 10, the size of the orifice 11 being just sufficient to receive the jet W with allowance for any slight spread of the latter. Practical tests have established that the jet W passes into the orifice 11 with little or no splash back and proceeds with considerable velocity along the return pipework 3 to the reservoir 4.

The outlet opening of the nozzle 1 may be of the order of .015" (0.4 mm) with the inlet orifice 11 slightly in excess of this size, e.g. for a jet W 12" to 18" (300 to 450 mm) long or thereabouts between the nozzle 1 and member 1 0. These figures are'quoted by way of practical example only and may be varied according to requirements. Thus jets W as short as 4" to 6" (100 to 150 mm) may be employed.

If the orifice 11 is made too large then run-back of water out of the orifice may occur with resultiny loss. In this connection and to avoid water loss when the jet W is turned off, a non-return valve 13 is shown provided in the return pipework 3 to prevent run-back of water from the latter out of the orifice 11. If desired the mouth of the orifice 11 may be outwardly tapered to assist entry of the jet W therein.

Under operating conditions the high pressure of the jet W is such that it cuts through blades of grass without deflection and with virtually no wetting of the grass so that the cutting means can be continuously operated for long periods without need to replenish the water supply.

In order to obtain a suitable width or swathe of the cutting action, multiple or gang arrangements of the cutting jets W may be employed in a cutting head or heads and as shown in FIGURES 2 and 3 with appropriate arrangements of nozzles 1 and collector members 10.

Thus the jets W are shown inclined to the direction T of travelling movement of the cutting head and with some overlap for continuity of the cutting action throughout the required width or swathe. In the twin jet arrangement shown in FIGURE 2 the jets W are directed in opposite directions to one another, whereas in the four jet arrangement shown in FIGURE 3 the jets W are all arranged in the same direction. However the number and arrangement of the jets W may be varied according to requirements.

Referring to FIGURES 4 and 5, multiple arrangements of nozzles 1 and collector members 10 are shown in relation to a finger bar 1 5 the fingers 1 50 of which serve to guide and locate blades of grass relative to the jets W with a comblike action.

The nozzles 1 and collector members 10 are preferably mounted underneath the finger bar 1 5 so that the jets W cut that part of the blades of grass held upright between the ground and the fingers 150. The nozzles 1 and collector members 10 are preferably shielded against impact with stones, roots or the like which might otherwise cause mis-alignment and/or damage.

The nozzles 1 and collector members 10 can with advantage be carried by the finger bar 1 5 and in FIGURE 5 wider fingers are shown at 151 for such mounting purposes, each intermediate wide finger 151 carrying a nozzle 1 and collector member 10.

At appropriate water pressure the cutting means can be also used for other cutting purposes such as hedge-cutting again by suitable mounting and operation of a cutting head or heads from a tractor or other vehicle. The cutting means also has more general application where recovery or collection of the water or other liquid after the cutting action is desirable or convenient, especially for re-circulation back to the outlet nozzle or nozzles.

Claims

1. High pressure liquid cutting means characterised by at least one nozzle for the discharge of a jet of water or other liquid at high pressure for cutting purposes, the nozzle being aligned with an inlet orifice of a collector member spaced therefrom for receiving the jet of water or other liquid in order to substantially recover the latter, e.g. for re-circulation to the nozzle.

2. High pressure liquid cutting means according to claim 1 wherein the inlet orifice of the or each collector member is of a bore size just sufficient to receive a high pressure jet of water or other liquid from a fine bore outlet opening of the or each corresponding nozzle in the order to minimise runback and loss of water or other liquid from the or each collector inlet orifice during operation of the cutting means.

3. High pressure liquid cutting means according to claim 1 or 2 comprising a pump for supplying water or other liquid at high pressure from a reservoir to the or each nozzle, the or each corresponding collector member being communicated by return passageway means to the reservoir for re-circulation of the water or other liquid received by the collector member or members.

4. High pressure liquid cutting means according to claim 1, 2 or 3 wherein the or each collector member communicates with a non-return valve.

e.g. in return passageway means to minimise runback and loss of water or other liquid from the passageway means through the or each collector member when supply of water or other liquid at high pressure to the nozzle or nozzles is stopped.

5. High pressure liquid cutting means according to any of the preceding claims wherein two or more arrangements of a nozzle and corresponding collector member are provided in a ganged or multiple arrangement in order to obtain a required width or swathe of the cutting action.

6. High pressure liquid cutting means according to claim 5 wherein overlap between adjacent arrangements of a nozzle and collector member is provided for continuity of the cutting action throughout the required width or swathe of the latter.

7. High pressure liquid cutting means according to any of the preceding claims wherein the nozzle and collector member or a ganged or multiple arrangement of two or more thereof are positioned in relation to a finger bar for guiding and location of material such as grass for cutting by a high pressure water or other liquid jet between the or each nozzle and corresponding collector member.

8. High pressure liquid cutting means according to claim 7 wherein the or each nozzle and corresponding collector member are carried by the finger bar such as by fingers thereof.

9. High pressure liquid cutting means according to claim 7 or 8 wherein the or each nozzle and collector member are mounted underneath the finger bar in position of use.

10. High pressure liquid cutting means according to any of the preceding claims wherein the nozzle the collector member or a ganged or multiple arrangement of two or more thereof and any finger bar therewith are carried by a cutting head, e.g. for grass cutting purposes.

11. High pressure liquid cutting means substantially as herein described with reference to any of the embodiments shown in the accompanying drawings.