Barking arrangement

Technical field:

The present invention relates to barking arrangements which operate with jets of water as specified in the introductory part of Patent Claim 1.

Background:

Previously dsiclosed are barking arrangements for logs in which the barking operation is performed with the help of one or more jets of pressurized water- A considerable water pressure is needed if the desired barking effect is to be achieved. In these previously disclosed arrangements use has been made for this purpose of some form of hydraulic pump by means of which the water was pumped through pipes to one or more nozzles from which jets of water were directed onto the object from which it was wished to remove the bark.

Technical problem:

Considerable losses have been found to occur in a barking arrangement of this construction^, as the result of which very high power was required for the pumping operation if an acceptable barking result was to be achieved within a reasonable time. Furthermore, an arrangement of this kind has also been found to be associated with high assembly costs, since it consists of a hydraulic pump, separate assemblies for the spraying and handling of the logs, and equipment to connect together these two parts.

The solution:

The application of the present invention has resulted in a barking arrangement which operates with water jets, in which the necessary hydraulic pump has been integrated with the spraying and handling equipment for the logs, thereby achieving the smallest possible losses in the production of the pressurized water.

Advantages:

The present invention means that it has been possible to simplify the arrangement in relation to said previously disclosed barking arrangements by being able to produce the pressurized water directly inside the barking arrangement.

Brief description of the drawings:

Illustrated in the accompanying drawings is an embodiment of the invention. Figure 1 shows a side view of a barking arrangement in accordance with the invention; Figure 2 shows a partially sectioned front view of the arrangement in accordance with the invention; Figure 3 shows a central section through the main part of the barking arrangement; and Figure 4 shows a view of a detail.

Best mode of carrying out the invention:

Attached to a base 1 as shown in Figure 1 are on the one hand an input housing 2 and on the other hand a frame 3 supporting the mechanical equipment of the barking arrangement, for which the reference designation 4 is used. The input housing 2 is connected to transport arrangements 5 for the logs 6 which are to be fed into the barking arrangement. The transport arrangements 5 may be of conventional type and will not, therefore, be described in any greater detail here. They must, however, be designed to feed the logs 6 from which it is wished to remove the bark one after the other from an input channel. The transport arrangements 5 shall be of the so—called self—centering type and shall thus feed the logs 6 into such a position that the centre—line of the different logs will Lie in essentially the same position in relation to the barking arrangement irrespective of the size of the Logs. Previously disclosed transport arrangements of this kind operate with chains moving horizontally for the purpose of transporting the Logs, said chains being shown in Figure 1 to be both super acent and subjacent chains which are so arranged as to centralize the Logs in relation to each other either with the help of a system of links or .b the positive positioning of the Logs under the control of an assembly which measures the thickness of the Logs.

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The bark which has been removed will be ejected from inside the input housing and is able to fall through a lower opening 7 in the housing 2 and down onto a conveyor belt 8 so arranged as to carry the bark to a dump. Such arrangements, too, have been previously disclosed and do not, therefore, require more detailed description. As may be appreciated from Figure 1, the housing 2 projects through the base 1 so as to permit the aforementioned connection with the conveyor belt 8 to be achieved,, The housing 2 is supported by the base 1 by means of a shock—absorbing rubber cushion ? in order to prevent vibrations from the housing being transmitted to the base.

For the purpose of feeding in the logs 6 an opening 11 is provided in a front wall 10 of the housing 2 , and in a rear wall 12 is a second hole 13 into which the mechanical part 4 of the barking arrangement extends for the purpose of receiving the logs. The chamber thus formed between the walls 10 and 12 contains the lower opening 7 .

The frame 3 is constructed in the form of a box with a front wall 15 and a rear wall 14 , through which walls extends a drum 17 provided with an entrance 16 constituting the fixed part of the mechanical part 4 and thus being supported by the frame. The frame 3 is also evident in Figure 2, which also shows parts of the rear wall 12 of the input housing 2 - It is also clear from the Figure how the drum 17 extends out of the housing 3 .

Figure 3 shows how the drum 17 extends out of the wall 15 of the frame 3 and is terminated at its outer end by' a funnel—shaped collar 18 which extends into the hole 13 in the rear wall 12 of the input housing 2 . This state of affairs is also clear from Figure 2. The outside of the drum 17 also exhibits seats for the bearings and sealing rings for two assemblies capable of rotating about the stationary drum 17 , referred to below as the water supply assembly 21 and the water outlet assembly 22 . The collar 18 is not attached directly to the drum 17 , but rather to a ring 20 which is connected by means of screws 1? to the rotating assembly 22 .

The water supply assembly 21 is thus supported by two

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deep—groove bearings 24 and 25 and consists of a tubular inner part 27 and an annular water housing 28 . The water housing 28 is supported by a flange 29 on the inner part 27 via an intermediate wall 30 . The intermediate wall 30 is enclosed within a tubular jacket 31 from which extend inwards towards the centre a front wall 32 and a rear wall 33 » Both walls exhibit a central hole 34 and 35 respectively, each of which is adjacent to an annular supporting column. The water housing 28 thus forms two annular chambers 36 and 37 respectively, of which the chamber

37 is referred to beLow as the inlet chamber and the chamber 36 as the outlet chamber. These two chambers are connected together via holes 38 in the intermediate wall 30 . Between the holes

38 are blades 39 .

The water supply assembly 21 exhibits in addition to the components already described a V-belt pulLey 44 which is screwed tightly to the inner part 27 and a number of sealing arrangements; a labyrinth seal 41 , a rubber seaL 40 and two diaphragm seals 42 and 43 are so arranged as to form enclosed spaces for the bearings 24 and 25 .

The water outlet assembly 22 itself exhibits two bearings 46 and 47 on the bearing seats on the drum 17 , said bearings supporting a drum—shaped inner part 49 with a flange 50 , which in turn supports not only a V-belt pulley 51 but also a pressurized water pipe 48 (alternatively, a number of pressurized water pipes may be provided, preferably arranged at an identical angular distance in relation to each other).

The pressurized water pipe 48 exhibits an axially arranged part 54 which is terminated towards the input end of the barking arrangement by a nozzle 55 facing essentially radialLy inwards towards the centre of the drum 17 , said nozzle being situated directly in Line with a hoLe 56 in the conical collar 18 ■>

The pressurized water pipe 48 ,exhibits a section 57 of pipe having a part 58 running radially and connected by means of an internal connector 59 to the pipe 54 _• The part 58 is terminated outwardly by a head which constitutes a pitot tube 60 .

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The pitot tube 60 and the part 58 are also shown in Figure 4, where they are viewed in the axial sense. As may be appreciated from Figure 4, the pitot tube has one end, this being its front end, with an opening 61 and another end, this being its rear end, with a droplet—shaped tip 62 . The cross—section of the part 58 is droplet—shaped, with the tapering part facing in the same direction as the tip 62 , so that the pipe section 57 will exhibit the lowest possible resistance when it moves in water with the opening 61 furthest to the front.

The water outlet assembly 22 also exhibits seals 70—73 . A pipe 64 is provided for the purpose of supplying water to the water supply assembly 21 , said pipe having an open end 65 situated inside the chamber 37 .

The intention is that the water outlet assembly 22 shall rotate on the drum 17 , so that the pressurized water pipe will move in such a way that the opening 61 of the pitot tube 60 will face forwards. At the same time the water supply assembly 21 is intended to rotate in the opposite direction^ The water supply assembly 21 must rotate at a higher speed than the water outlet assembly. Appropriate speeds are 1500 r/miη for the water supply assembly and 800 r/min for the water outlet assembly. Electric motors are provided for the purpose of driving both assemblies. These are connected by V—belts to the two belt pulleys 44 and 51 . This is illustrated in Figure 2, in which an electric motor 66 with a belt pulley 67 and also V-belts 68 are shown.

The operation of the barking arrangement requires the two assemblies to rotate, including the water outlet assembly 22 as has already been mentioned, so that the opening 61 of the pitot tube 60 will face towards the front, and with the water supply assembly 21 rotating in the opposite direction. Through the pipe 64 is supplied water, which flows out into the chamber 37 through the open end 65 . The blades 39 carry this water along with them,, and a water ring is formed through centrifugal force inside the chamber 37 . The volume of the water ring is restricted by the hole 35 , which will permit water to be released over its edge. Alternatively, the end 65 of the pipe 64 may be caused to be

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situated inside the edge of the hole 35 _κ , and at a restricted and appropriately set pressure in the pipe 64 this will enable the counter—pressure created by centrifugal force in the water ring to hold back the arriving flow, so that the water ring will be terminated inwardly more or less at the end 65 of the pipe 64 .

The water carried around by the blades 39 as they rotate will be forced out by centrifugal force through the openings 38 and into the chamber 36 . It is thus this flow of water which is to be replaced by the flow arriving through the pipe 64 , so that the aforementioned water ring will always be present inside the chamber 37 .

A water ring of which the internal diameter is restricted by the hole 34 wiLL also be formed inside the chamber 36 . This water ring will thus move together with the rapidly moving water housing 28 , and the pitot tube 60 and parts of the the radial component 57 will project into the water ring. Since the pitot tube together with the water outlet assembly 22 move in the opposite direction to the water ring, the relative speed between the head of the pitot tube 60 and the water ring will be the sum of the peripheral speeds of the water ring and the pitot tube. The water will thus approach the front end of the tube 60 at high speed and will enter the opening 61 and will be forced to travel further by the radial component 58 through the connecting tube 59 , via the axial component 54 and out through the nozzle 55 . The jet of water formed in this way will flow radially inwards towards the centre of the entrance 16 in the drum 17 through the opening 56 in the conical collar 18 .

Once a jet of pressurized water (or a number of jets corresponding to several pitot tubes) has been generated in the manner described, the logs 6 can begin to be fed in by means of the transport arrangement 5 « The Logs will move in sequence one after the other through the input housing 2 and into the conical col ar 18 and then further through the entrance 16 to the drum 17 . In this way they w LL move past the jet of pressurized water rotating about the centre of the entrance 16 at the speed of rotation of the water outlet assembly 22 .

As they pass through the arrangement, the circumference of the logs will be swept over in the form of a spiral by the jet of water, and since the rate of feed of the logs is relatively low in relation to the speed of rotation of the water outlet assembly, the ci cumference of the logs will be treated in its entirety by the jet of water. Because of the dynamic forces which arise in the course of the procedure outlined here, the pressure of the jet of water will be very high and will possess a considerable treatment capacity, with the result that the timber in the logs will be stripped of bark, gravel, ice and any other substances which may be present on the surface of the logs as they are fed in.

Since the pressurized water is produced directly inside the barking arrangement in very close proximity to the nozzle, the effect generated by the creation of the pressure is utilized in the best possible fashion. A further advantage is that the jet of water can also be made to orbit around the log, so that the latter need not be rotated. There is thus no need to provide any swivel couplings, which would be necessary in the case of an assembly having a fixed pump and a rotating nozzle.