GB2138052A

GB2138052A - A method of extracting peat from moss and equipment for carrying out the method

Info

Publication number: GB2138052A
Application number: GB08309493A
Authority: GB
Inventors: Timo Nyronen
Original assignee: Valtion Polttoainekesus
Current assignee: Valtion Polttoainekesus
Priority date: 1983-04-07
Filing date: 1983-04-07
Publication date: 1984-10-17

Abstract

A method of extracting peat from moss and equipment for carrying out the method. A method of extracting peat from moss as a mixture of solids and water comprises extracting the mixture by means of a suction pipe (2, 3), the mouth (4) of which is placed beneath the surface layer (5) of the moss between the surface (5) and the firm bottom (9) therebeneath. <IMAGE>

Description

SPECIFICATION A method of extracting peat from moss and equipment for carrying out the method The invention is concerned with a method of extracting peat from moss, in which the peat is extracted as a mixture of solids and water.

According to the prior-art methods usually used, costly and time-consuming preparatory work must first be carried out on the moss before it is possible to start production of peat. For example, for the production of milled peat, the moss must first be drained by means of drainage ditches. After a period of waiting of several years, after the moss has been drained, the trees on the moss must be removed and the ground must be levelled before production commences. In addition to the high cost of these preparations, a further drawback of this method is that, as a result, extensive changes are produced in the peat.

For the extraction of wet peat, without draining the moss, several methods have also been developed. For example, the excavation of peat from underneath the water surface in a similar way to suction dredging has been suggested in U.S. Patents 962120 and 1476407. According to those methods, a pump is located on a raft floating on the surface, with a suction pipe connected thereto. The free end of the suction pipe is provided with a cutter device for detaching the peat from the bottom. The extraction of the peat takes place by moving the cutter at the end of the suction pipe along the bottom.

The cutter detaches the peat from the bottom and, at the same time, a mix of solid peat material and water is formed which can be sucked by means of the pump along the suction pipe up onto the raft and from there further to subsequent processing. It is a drawback of this method that it requires complicated and extensive equipment. The raft must also be shifted continually as the peat is exhausted at one place. Nor is it possible to move the raft on the moss unless the depth of water is sufficient, or if there is abundant surface vegetation on the moss. The present invention seeks to eliminate or reduce some or all of the above drawbacks and to provide an efficient method for the extraction of peat from wet moss.According to a first aspect of the invention, there is provided a method of extracting peat from moss as a mixture of solids and water, wherein the mixture of solids and water present in the moss is extracted by means of a suction pipe, the mouth of which pipe is placed underneath the surface layer of the moss between the surface and the firm bottom therebeneath. Further according to this aspect, there is provided a method of extracting peat from moss as a mixture of solids and water, wherein the layer between the surface of the moss and the firm bottom is crushed to obtain an appropriate mix of solids and water for extraction by means of a suction pipe. Thus the peat is extracted from beneath the surface, whereby the surface moss layer remains almost intact. In this way only the mouldered peat material underneath the surface is recovered.The poorly mouldered surface layer would, in any case, not be used, e.g., as fuel peat. No laborious preparatory work is required. Only the placing of the mouth of the suction pipe underneath the surface is essential. By means of the invention, peat can be extracted from undrained moss around the year. It can be accomplished in different ways, which again depend on the specific features of the moss, such as the type of peat, degree of mouldering, thickness of the peat layer, depth of frost, stone contents, and quantity of wood material.According to a second aspect of the invention, there is provided equipment for the extraction of peat from moss comprising at least one suction pipe and at least one pump for suction of the peat as a mixture of solids and water, wherein the end of the suction pipe connected to the pump is passed through the surface layer of the moss between the surface and the firm bottom. Further according to this aspect of the invention, there is provided equipment for the extraction of peat from moss, comprising at least one suction pipe and at least one pump for suction of the peat as a mixture of solids and water, wherein the suction pipe connected to the pump is located underneath the surface of the moss, and substantially parallel thereto.Still further according to this aspect, there is provided equipment for the extraction of peat from moss comprising at least one suction pipe and at least one pump for extraction of the peat as a mixture of solids and water, wherein the equipment comprises a collector pipe parallel to the surface of the moss and two or more suction pipes substantially parallel to the surface and connected to the collector pipe, the ends of the suction pipes being provided with substantially vertical portions so that the mouth of the suction pipe is located between the surface layer of the moss and the bottom. Several examples of the method of the invention will now be described.

Example 1 A pipe system is installed into the moss below the frost limit. The spacing of the pipe system and the length of the individual pipes depend on the conditions present in the moss.

The individual pipes are connected to a collecting pipe, which is connected to a pump.

This example is based on the principal that, when the peat/water mix is being pumped at an appropriate rate, the "cavity" formed at the open ends of the pipes is filled owing to the sinking of the peat, and the system is consequently in continuous operation. This method requires a high water content in the moss. The pipes used may be made of plastics, and can be removed from the moss after completion of the peat extraction.

Example 2 At the open end of an individual pipe, a device is provided which, operating by means of a water jet, detaches the peat and pushes it into the pipe. In this example, the pipe "eats" itself into the moss while proceeding horizontally. For example, an ejector may be formed at the mouth of the suction pipe so as to produce the mix of peat and water by means of a water jet.

An individual pipe may be pulled out of the moss if it meets an obstacle which it cannot by-pass. The individual pipes are connected to a collecting pipe, along which the detached peat/water mix is pumped.

Example 3 The extraction of peat takes place from within the moss by means of a suction nozzle of special contruction. The suction pipe is a so-called double pipe, in which water flows in the inner pipe to the suction nozzle and the peat sludge flows in the outer pipe to the sludge pump. The function of the water passing to the suction filter is to promote the passage of the peat into the suction pipe as well as to dilute the peat to be extracted so that it can be pumped readily.

In view of the operation, the most ideal solution is, according to this example, one in which the suction pipe system is a stationary pipe system placed in the moss, and thus, in winter, underneath the ice. Vertical suction pipes are connected to the collecting suction pipe, which is sunk down to a depth of at least 60cm from the moss surface. As the frost depth of a peat moss is, according to experience, about 30 to 50cm, the problem of freezing of the suction pipe system is avoided. The density of spacing of the "sewage network" in a peat moss depends on the flow properties of the moss and varies according to the degree of mouldering of the moss.

The flow properties of a moss can be improved by blasting the bottom of the moss with powerful explosive charges before the suction is started or if the flow of peat into the suction pipe has started weakening. If required by the circumstances, the suction pipe system may also be constructed to be movable.

Example 4 The pipe system intended for shifting the peat is dug into the moss beneath the frost limit, or it is insulated from above so that freezing is excluded under all circumstances.

The number and spacing of suction heads is chosen in dependence on the flow properties of the moss. The water removed during draining of the peat may be passed either back onto the production moss or to elsewhere.

The mouth of the suction pipe may be provided, e.g., with a mechanical crusher, and the mouth of the suction pipe may be shaped as an outwardly opening funnel. The suction heads with the crushers are pushed close to the moss bottom in order that the effective range of operation of each suction head should be as large as possible. The suction heads and the pipe system are built so as to be as light as possible, in order that their movement should be as easy as possible. the area to be worked at one time must, however, be at least large enough to satisfy the requirement of raw peat for the winter season. The pipe system can be kept at the desired level, e.g., by means of pontoons, which may consist e.g., of "Styrox" polystyrene insulation blocks.An essential feature of this embodiment of the invention is a stationary nonfreezable transfer pipe system having several suction points as well as the possibility of operation of the suction points independently from each other. This permits an alternating operation of different suction points, as necessary, owing to the slow flowing properties of peat. If the output from the main pipe is reduced, the suction point is changed. This is possible, because each suction point is provided with a pump and an electric motor of its own. Advantages of the wet extraction of peat as described above are harmony with the environment, low enery requirements, annd little preparatory work. Moreover, the moss can be exploited with a shorter delay, as compared with the present-day technology, and the extraction of peat can be continued throughout the year.The method can also be employed in low-peat areas, but in such a case, the extraction must be performed when the temperature is above zero. A further advantage is that the surface layer of the moss, the sphagnum peat and the vegetation therein, remain almost intact. Likewise, the high costs of digging ditches for draining and of clearing the ground are avoided. Equipment in accordance with the invention will now be described in greater detail, by way of example, with reference to the drawings, in which: Figure 1 is a schematic plan view of the equipment in accordance with the invention; Figure 2 shows a section along the line 11-1 1 of Figure 1; Figure 3 shows a vertical section of a second embodiment of the invention; Figure 4 shows a vertical section of a third embodiment of the invention; and Figure 5 shows the equipment shown in Figure 4 as viewed from above.

The embodiment shown in Figures 1 and 2 is provided with a collector pipe 1, to which suction pipes 2 are connected. The collector pipe 1, whose diameter is, e.g., 1 00mm, is connected to a pump (not shown). The ends of the suction pipes 2 are provided with vertical portions 3 in order that the mouth 4 of the suction pipe should be within the region between the surface layer 5 of the moss and the bottom 9. It is seen from the figures that the suction pipe portion 2 parallel to the surface is substantially at the level of the moss surface layer 5. For winter conditions, the suction pipe 2 is covered with a heat insulation 6. The heat of the water remaining unfrozen in the moss then prevents freezing of the pipes.The mouth 4 of the suction pipe shown in Figure 2 is further provided with a crusher 7, for agitating the mix 10 of peat and water so as to make it suitable for suction. At the same time, it prevents blocking of the mouth 4 of the suction pipe. However, no crushing or cutting of the bottom 9 is concerned.

Figure 3 shows an embodiment in which the collector pipe 1 from the pump 8 and the horizontal portions 2 of the suction pipes are placed on the moss surface. In operation throughout the year, the pipes must, of course, be well insulated. The vertical portiosn 3 of the suction pipes are located through the surface layer 5 of the moss so that the mouth 4 of the suction pipe 3 is located between the surface and the bottom 9.

Figures 4 and 5 show an embodiment in which the suction pipes 2 are located parallel to the moss surface 5 but substantially underneath it. The suction pipes 2 are connected via the collector pipe 1 to the pump 8. In this embodiment, the suction pipes 2 may be allowed to move freely in the moss in the mix 10 of water and solids between the moss surface and the bottom 9. The movement of the suction pipe 2 takes place, for example, as a result of the effect of the counter-force resulting from the suction in the pipe. The suction pipe may comprise a plastics material and may have a diameter e.g., from 20 to 100mm. According to a preferred embodiment, the diameter of the suction pipe is 40mm. It can be imagined that the mix of water and solids in the moss is homogeneous so that there is no distinct interface between the solid material and the liquid.The mix ordinarily contains, e.g., 3 to 6 per cent by weight of solid material. If the content of solids is higher than 10%, the pumping of the mix involves difficulties. In such a case, water may be introduced in the proximity of the mouth of the suction pipe, whereby the mix can be pumped more readily. The thickness of the peat layer in the moss is usually about 2.5 to 4 metres. As peat is extracted, this layer is of course reduced. Thus, the appropriate peat mix to be sucked by pumping may be momentarily exhausted at the proximity of the mouth of one or more of the suction pipes.

The suction may then be interrupted in respect of that suction pipe and another suction pipe may be used. Then, as can be appreciated, the moss flows radially towards the mouth of the non-operating suction pipe, and after some time the pumping cna be resumed.

The installation of the pipe systems in the moss may be performed, for example, by means of underdraining, whereby the pipe is lowered into a narrow dug trench and covered. For operation throughout the year, it is essential that the pipes are placed below the frost limit. If the pipes are placed in the peat material layer to be sucked, which consists mostly of water, they can be kept at the correct depth, e.g., by means of pontoons.

Claims

1. A method of extracting peat from moss as a mixture of solids and water, wherein the mixture of solids and water present in the moss is extracted by means of a suction pipe, the mouth of which pipe is placed underneath the surface layer of the moss between the surface and the firm bottom therebeneath.

2. A method of extracting peat from moss as a mixture of solids and water, wherein the layer between the surface of the moss and the firm bottom is crushed to obtain an appropriate mix of solids and water for extraction by means of a suction pipe.

3. A method as claimed in claim 1 or 2, wherein at least one suction pipe is pushed through the surface layer of the moss, the mouth of the pipe being located between the surface and the bottom.

4. A method as claimed in claim 1, 2 or 3 wherein two or more suction pipes are pushed through the surface layer of the moss, the said suction pipes being connected to a collector pipe.

5. A method as claimed in claim 1 or 2, wherein at least one suction pipe is positioned underneath the surface layer of the moss substantially parallel to the surface.

6.A method as claimed in claim 5, wherein the suction pipe is allowed to move forwards in the moss as a result of the counter-force resulting from the suction of the pipe.

7. A method as claimed in claim 1, 2 or 5, wherein a plurality of suction pipes are located underneath the surface layer of the moss, substantially parallel thereto, and are connected to a collector pipe.

8. A method as claimed in claim 5 or 7, wherein the pipe or pipes parallel to the surface of the moss is or are installed underneath the surface layer by means of the underdraining method, i.e. the pipe or pipes is or are lowered into a ditch dug for the pipe.

9. A method as claimed in claim 5, 7 or 8, wherein the pipe or pipes parallel to the moss surface is or are installed at a depth below the frost limit.

10.A method as claimed in any one of claims 5 or 7 to 9, wherein the pipe or pipes parallel to the moss surface is or are kept at the desired distance from the surface by means of pontoons.

11. A method as claimed in any one of claims 1 to 4, wherein a collector pipe is located in proximity to the moss surface and parallel thereto and heat insulation preventing freezing is placed over the pipe.

1 2. A method as claimed in any one of claims 1 to 11, wherein a collector pipe for the suction pipe or pipes is stationarily located and the suction pipe or pipes is or are movable so that the location of the mouth or mouths of the suction pipe or pipes is or are variable.

1 3. A method as claimed in any one of claims 1 to 12, wherein the suction operation is controlled such that each suction pipe can be separately brought into operation and out of operation.

14. A method as claimed in claim 1, 2 or 13, wherein the suction pipes are operated in a desired sequence.

1 5. A method as claimed in any one of claims 1 to 14, characterized in that the desired distance of the mouth of the suction pipe or pipes from the- moss surface is kept maintained by means of a pontoon attached to the suction pipe.

16. A method as claimed in any one of claims 1 to 14, wherein the mouth of the suction pipe is located at a desired distance from the bottom of the moss.

1 7. A method as claimed in any one of claims 1 to 16, wherein water is introduced into the peat in the proximity of the mouth of the suction pipe in order to facilitate the suction operation.

1 8. A method as claimed in any one of claims 1 to 17, wherein a jet of water is introduced into the mouth of the suction pipe so that suction of the mix of peat and water is carried out by means of an ejector method.

1 9. A method as claimed in any one of claims 1 to 1 a, wherein water is introduced in the proximity of the mouth of the suction pipe, and is separated from the mix of peat and water extracted from the moss.

20. A method as claimed in any one of claims 1 to 19, wherein water is separated from the mix of peat and water extracted from the moss, and is passed back onto the moss surface.

21. A method as claimed in any one of claims 1 to 20, wherein the layer between the surface layer of the moss and the bottom is agitated by means of a water jet introduced in the proximity of the mouth of the suction pipe.

22. A method as claimed in any one of claims 1 to 20, wherein the layer between the surface layer of the moss and the bottom is agitated by means of a mechanical crusher.

23. A method as claimed in any one of claims 1 to 20, wherein the layer between the surface layer of the moss and the bottom is agitated by blasting of an explosive charge in this layer.

24. Equipment for the extraction of peat from moss comprising at least one suction pipe and at least one pump for suction of peat as a mixture of solids and water, wherein the end of the suction pipe connected to the pump is passed through the surface layer of the moss so that the mouth of the suction pipe is located underneath the surface layer of the moss between the surface and the firm bottom.

25. Equipment as claimed in claim 24, wherein two or more suction pipes pass through the surface layer of the moss and are connected to the pump by means of a collector pipe.

26. Equipment for the extraction of peat from moss, comprising at least one suction pipe and at least one pump for suction of the peat as a mixture of solids and water, wherein the suction pipe connected to the pump is located underneath the surface of the moss, and substantially parallel thereto.

27. Equipment as claimed in claim 26, wherein two or more suctions pipes are provided beneath the surface layer of the moss and substantially parallel thereto, the suction pipes being connected to the pump by a collector pipe.

28. Equipment as claimed in any one of claims 24 to 27, wherein a pontoon is attached to the suction pipe for the purpose of keeping the mouth of the suction pipe at a desired distance from the surface of the moss.

29. Equipment as claimed in any one of claims 24 to 28, wherein the suction pipe has two channels, one for supplying water to the proximity of the mouth of the suction pipe and the other for carrying the mix of peat and water.

30. Equipment as claimed in claim 29, wherein an ejector is provided at the mouth of the suction pipe for suction of the mix of peat and water by means of a water jet.

31. Equipment as claimed in claim 29 or 30, wherein a nozzle is attached to the mouth of the suction pipe to provide a water jet for agitating the layer between the moss surface and the bottom.

32. Equipment as claimed in any one of claims 24 to 31, wherein a mechanical crusher is attached to the mouth of the suction pipe.

33. Equipment as claimed in any one of claims 24 to 32, wherein the mouth of the suction pipe has the form of an outwardly opening funnel.

34. Equipment for the extraction of peat from moss comprising at leat one suction pipe and at least one pump for extraction of the peat as a mixture of solids and water, wherein the equipment comprises a collector pipe parallel to the surface of the moss and two or more suction pipes substantially parallel to the surface and connected to the collector pipe, the ends of the suction pipes being provided with substantially vertical portions so that the mouth of the suction pipe is located between the surface layer of the moss and the bottom.

35. Equipment as claimed in claim 34, wherein the collector pipe and the suction pipes, both of which are parallel to the surface of the moss, are located close to the surface of the moss and are covered with heat insulation.

36. Equipment as claimed in claim 34, wherein the collector pipe and the suction pipes, both of which are parallel to the moss surface, are located below the frost limit.

37. Equipment as claimed in claim 34, 35 or 36, wherein a peat crusher is attached to the mouth of each suction pipe at their vertical portions.

38. A method of extracting peat from moss substantially as described herein with reference to the examples.

39. Equipment for extracting peat from moss substantially as described herein with reference to the drawings.