GB2071560A - Straw logs - Google Patents

Abstract

A machine for processing straw into log-like units, suitable for subsequent burning on a domestic open fire, comprises means to spray the straw with a hardenable binding agent and means to compress the mixture of straw and binding agent into the desired log-like shape. The spraying means consists of a ring of nozzles (16) through which the straw passes after first being picked and elevated onto the machine. The compressing means comprises a power-operated piston (12) moving within a chamber (14) whose cross section is that of the shape desired. The mixture of straw and binding agent is transported to the piston (12) by a first piston (11). As the first piston (11) transports the mixture to the breach of the chamber (14), it progressively seals off the continuing mixture infeed. The finished logs are ejected into a hopper (21). The machine can be mounted on a wheeled chassis (not shown) and pulled behind an agricultural tractor to pick, elevate, transport and compress the straw.

Description

SPECIFICATION Straw logs The invention relates to a method of processing straw into log-like units which can subsequently be burned on a domestic open fire; and also to a machine for carrying out such a method.

In this country, thousands of tons of straw are burned every year, either because there is no market for this quantity of straw, or because the straw itself is not of the right quality, or both. This represents a waste of natural resources.

This over-produced or under-quality straw could instead be used to subsidize our national fuels, by being burned to create useable domestic heat. However, straw which has been picked, and even baied, is not suitable for burning in domestic open fires. Straw as a picked material tends to be messy. Straw in bales is usually far too large for a domestic open fire to handle, and is still messy.

Straw burning stoves exist, but these tend to be large and expensive and are closed units.

The invention seeks to find a use for the otherwise wasted straw, in particular to make it possible for this straw to be processed into loglike units which an subsequently be burned on a domestic open fire.

The present invention starts from the realisation that straw, even when baled, tends to disintegrate when handied. Baling reduces this tendency, but baling machines are expensive, and hand-baling, whilst cheaper, is tedious.

The inventive concept is based on a process of first spraying onto a quantity of the straw a hardenable binding agent and then compressing the mixture of straw and binding agent into the desired log-like shape.

Using such a method, baling is not needed, but the binding agent, once hardened, reduces the tendency of the straw to disintegrate. The log-like units resulting from use of the method can be handled without excessive mess in domestic premises, and can be made small enough to be subsequently burned on a domestic open fire.

A machine embodying the invention comprises means for spraying onto a quantity of the straw a hardenable binding agent; means for transporting the mixture of straw and binding agent into a chamber whose walls define the cross section of the desired log-like shape; means for compressing the mixture of straw and binding agent within the chamber to cause the mixture to assume, at least in cross section, the desired log-like shape; means for opening the chamber to allow the compressed log-like mixture to be removed from the chamber; and means to repeat the above sequence of operations for a desired number of times.

When such a machine operates, each sequence of operations produces as least one log-like unit.

The machine can be made simple yet effective by using the minimum number of moving and sequentially linked parts, without the complications needed in the conventional straw baling machine with its bale-forming and twine-tying mechanisms.

In one machine embodying the invention, the means for transporting the mixture into the chamber and for compressing the mixture within the chamber comprise two power-operated pistons, a first of which transports the mixture into the breach of the compression chamber, and the second of which transports that mixture from the breach into the chamber and then compresses the mixture within the chamber; and the first piston, as it transports the mixture into the breach, progressively seals off the chamber, and keeps it sealed during the transporting and compressing movements of the second piston, before subsequently withdrawing to transport to the breach the mixture to be compressed in the next operational sequence of the machine.

With such an arrangement, the transporting and compressing of the mixture of straw and binding agent is accomplished rapidly and effectively by only two major moving secquentially linked power-operated units.

In the arrangement just outlined, the first piston, as it transports the mixture into the breach, may also progressively cut off any continuing infeed of mixture from the spraying means towards the mixture-receiving station of the first piston. This again uses the component parts of the machine to maximum effect, by making them perform more than one function, and helps to keep the machine relatively simple and trouble-free in use.

The first piston, having transported the mixture into the breach-may then occupy a position in which the end face of the first piston seals off the chamber by forming, with the walls of the breach and the end face of the second piston during its transporting movement -- or during its transporting and its compressing movements may then move across the end face of the first piston. The end face of the first piston then effectively constitutes a wall of the breach, or the chamber, or both; and again the component parts of the machine are used to maximum effect.

In any of the arrangements outlined above, where two power-operated pistons are used, the paths of movement of the pistons are preferably substantially at right angles to one another. This makes it easier to achieve, in particular, the arrangement outlined in the last paragraph.

The paths of movement of the pistons may conveniently be linear. This makes it possible to use readily-available components, such as linearstroke power-operated hydraulic or pneumatic rams. In this way the cost of the machine are kept down and the likely operating reliability is increased.

A machine embodying the invention is shown in the accompanying drawings. It is only one example of forms which the invention may take. It will now be described with reference to the drawings, in which: Figure 1 shows the machine during the initial spraying of straw and its subsequent infeed to the mixture-receiving station of a first piston of the machine; Figure 2 shows the same machine with its first piston having transported the mixture into the breach of a compression chamber of the machine, and having sealed off the breach and the mixture infeed; Figure 3 shows the machine with its second piston in the act of transporting the mixture into the compression chamber and beginning to compress the mixture into the desired log-like shape; and Figure 4 shows the compressed log-like unit being removed from the compression chamber as the second piston withdraws back into the breach of the chamber.

All drawings are diagramatic illustrations of the operation of the main parts of the machine, sufficient to enable the man skilled in this particularly art to put the invention into practise, but not intended in any way to supply details which the skilled man will provide without need of any further inventive thought.

As shown, the machine consists essentially of two pistons and their associated chambers. The lines of action of the pistons are each linear. They are substantially at right angles to one and other.

Each piston is carried on the rod end of a hydraulic double-acting ram. The first piston is referenced 1 the second piston is referenced 12, and the two rams are referenced respectively 1 A and 12A.

The first piston operates within the confines of a linear elongate chamber whose walls are indicated generally by the reference numeral 13 and which is square in cross section. The second piston operates, during its compression movement, within the confines of a chamber which is circular in cross section and which is elongate. It is referenced 14 in the drawings.

These major parts of the machine are mounted on a wheeled chassis (not shown in the drawings), together with a straw-picking mechanism (also not shown); an elevator and conveyor, the delivery end of which is referenced 1 5 in the drawings; anc a ring of nozzles referenced generally 1 6 and situated adjacent the delivery end of the conveyor.

The wheeled chassis which carries the component parts of the machine is adapted to be pulled, in use, by an agricultural tractor (not shown) and the hydraulic power necessary to operate the rams 1 A, 1 2A is taken from the tractor by connections which are well known in themselves.

Any electrical or other power necessary to operate the straw-picking mechanism and the straw elevator and conveyor is also provided from the tractor. The reservoir of binding agent which will be referred to later, and which is supplied under pressure to the ring of nozzles 16, is supplied by an electric pump which is driven from the tractor. The reservior of binding agent which feeds the nozzles through the pump may be carried on the tractor or on the wheeled chassis of the machine itself; the reservoir is not shown in the drawings.

When the machine operates, straw is picked off the stubble onto the elevator and is passed through the chaff cutters to break up the straw.

The chaff cutters are not shown in the drawings: they are will known in themselves, as is the strawpicking mechanism. From the cutters, the straw is fed by the conveyor 1 5 past the ring of nozzles 1 6.

The nozzles are so angled that they spary into and around the staw a hardenable binding agent. The binding agent could be an adhesive, or a vegetable resin. It is in liquid form and is sprayed in a relatively fine mist through the nozzles, but it could comprise powdered solids or even relatively large solid pellets which were sprayed into the centre of the moving mass of straw. Suitable particulate forms for the binding agent will depend on the particular agent used.

The mixture of straw and resin is carried by the conveyor 1 5 into a primary chamber referenced 17. This primary chamber is formed at one end of the chamber 13 in which the first piston 1 1 moves. When a predetermined quantity of straw and resin has accumulated in the primary chamber 17, the ram 1 a extends the piston 11 to transport the mixture into the breach 18 defined between the two chambers 13 and 14.

As the piston 11 transports the mixture of straw and resin into the breach 18, one side 1 B of the square piston 11 automatically and progressively closes off the infeed of mixture from the conveyor 1 5. This infeed, which arrives at a relatively slow constant rate from the conveyor, simply continues to accumulate against the side of the piston until the piston is subsequently withdrawn as will be described later.

Figure 2 shows the piston 11 in its fully extended position. The side 11 B of the square piston 11 has cut off the mixture infeed from the conveyor 15, and the end face 1 C of the piston forms, with the walls of the breach 18 and the end face 12C of the piston 12, and extension of the chamber 14.

Referring now to Figure 3, with the piston 11 remaining in its figure 2 position, the second piston 12 is extended by its ram 1 2A. The second piston 12 transports the mixture from the breach 18 into the compression chamber 14. As it does so, it moves across the end face 1 1C of the first piston 11.

Once the end face of the piston 12C enters the chamber 14, the mixture of straw and resin begins to become compressed. The chamber 14 is so sized and shaped that, at least in cross section, it reproduces the shape in which the finished loglike units are to be produced. The end of the chamber 14 remote from the breach 1 8 is closed, during the compression movement of the piston 12,byagate 19.

With the piston 12 fully extended, to a position (not illustrated) about one third of the way down the chamber 14, the gate 19 is opened. The inherent resilience of the compressed mixture of straw and resin causes the now-log-like unit to project from the discharge end of the chamber 14 as shown in Figure 4. The compressed unit linearly expands to the state shown in Figure 4. It then falls under gravity into a hopper 21.

When the gate 1 9 is opened, the piston 12 automatically withdraws and returns eventually to the position which it occupies in Figures 1 and 2 of the drawings. Throughout this movement, the piston 11 remains in its Figure 3 and Figure 4 position. When the piston 12 has withdrawn fully, the piston 11 is withdrawn also to its Figure 1 position. As it does so, it automatically opens again the infeed from the delivery end of the conveyor 15; and the sprayed mixture which has been accumulating there is then pushed into the mixture-receiving station 1 7.

Preferably the hardenable binding agent comprises a heat-hardenable agent, since this has several advantages. As the mixture is being compressed in the chamber 14, frictional heat will be produced in the inside of the chamber and this may promote hardening of a "skin" around the eventual log whilst leaving the inside of the straw log still resiliently pliable. The "skin" resists disintegration of the log when the log falls eventually into the hopper 21.

If the binding agent is also flammable, it will help the log to burn eventually on a domestic fire.

It is conceivable that non-flammable binding agents could be used. They may leave ash or other deposits, and for that reason they are not as desirable as flammable binding agents.

A succession of log-like units is ejected from the discharge end of the chamber 14 into the hopper 21 by repeating the sequence of operations outlined above. The logs can at will be dispensed into a tractor drawn trailer or lorry (neither shown in the drawings) to be removed from the field in which the straw is growing.

To increase the yield of logs, without choking the machinery or multiplying it unnecessarily, a single piston 11 could supply several secondary transporting and compressing pistons 12, so that several logs could be formed and ejected simultaneously from chambers such as the chamber 14. One log would be ejected from each chamber, at a time, but there would be several chambers each filled and compressed simultaneously by several pistons such as the piston 12 all working in unison.

It is envisaged that up to two rows of combined straw could be picked up at one time.

The "log-like" units could be cylindrical, as illustrated, or they could be rhomboid, for example rectangular; or cube-shaped, in which case they would preferably be fairly small.

Suitable hardenable binding agents can be selected without invention by the man skilled in this particular field. It is also well within the uninventive scope of the skilled man to decide limits to the pressures needed to form the compressed logs: they are of course compressed by an amount which is sufficient to form a unit resistant to disintegration whilst not sufficient to set the log on fire in the machine.

Claims (8)

1. A method of processing straw into log-like units which can subsequently be burned on a domestic open fire, the method comprising the steps of first spraying onto a quantity of the straw a hardenable binding agents and then compressing the mixture of straw and binding agent into the desired log-like shape.

2. A machine for processing straw into log-like units which can subsequently be burned on a domestic open fire, the machine comprising means for spraying onto a quantity of the straw a hardenable binding agent; means for transporting the mixture of straw and binding agent into a chamber whose walls define the cross section of the desired log-like shape; means for compressing the mixture of straw and binding agent within the chamber to cause the mixture to assume at least in cross section the desired log-like shape; means for opening the chamber to allow the compressed log-like mixture to be removed from the chamber; and means to repeat the above sequence of operations for a desired number of times.

3. A machine according to Claim 2, in which the means for transporting the mixture into the chamber and for compressing the mixture within the chamber comprises two power-operated pistons, a first of which transports the mixture into the breach of the compression chamber, and the second of which transports that mixture from the breach into the chamber and then compresses the mixture within the chamber; and the first piston, as it transports the mixture into the breach progressively seals off-the chamber, and keeps it sealed during the transporting and compressing movements of the second piston, before subsequently withdrawing to transport to the breach the mixture to be compressed in the next operational sequence of the machine.

4. A machine according to Claim 3, in which the first piston, as it transports the mixture into the breach, progressively cuts off any continuing infeed of mixture from the sparying means towards the mixture-receiving station of the first piston.

5. A machine according to Claim 4 of Claim 3 in which the first piston, having transported the mixture into the breach, occupies a position in which the end face of the first piston seals off the chamber forming, with the walls of the breach and the end face of the second piston, an extension of the chamber; and the second piston, during its transporting movement -- or during its transporting and its compressing movements moves across the end face of the first piston.

6. A machine according to Claim 5 or to Claim 4 or to Claim 3 in which the paths of movement of the pistons are substantially at right angles to one another.

7. A machine according to any of Claims 6, 5, 4 and 3, in which the paths of movement of the pistons are linear.

8. A machine for processing straw into log-like units which can subsequently be burned on a domestic open fire, the machine being constructed and arranged to operate substantially as described herein with reference to, and as illustrated in, the accompanying drawings.