Patent Description:
<CIT> discloses a device for feeding a threading tail into a tape for threading tail. The threading tail of the pulp web is passed through the dryer by means of a tape. The tape is an endless narrow belt running through the dryer. The belt is a fabric made of jute or aramid for example. The tape has two parts seamed together from one side. In this way, the parts can be opened, and the threading tail can be put between the parts. The threading tail is fed into the opened tape and then the tape is closed again. The closed tape keeps the threading tail in the grasp and leads the threading tail through the pulp dryer. After the pulp dryer the tape is opened, and the threading tail is released and dumped into the pulper. <CIT> discloses a multi-pass web-treating apparatus particularly adapted for drying a paper web according to the preamble of claim <NUM>.

The tape is narrow, but about <NUM> to <NUM> meters long and it is supported with several guides. The tape is quite heavy with two parts and the tape pulls the threading tail through the pulp dryer. Thus, the guides need to withstand pulling but also has to keep the tape under control. The guide includes a rotating wheel or equivalent.

There are many problems with the known technology. The guides are difficult to adjust. The run of the guide cannot be adjusted while the tape is running. In practice, the tape must always be stopped completely, and the tension of the tape is also released before the adjustment. Thus, the adjustment is laborious and time consuming. In many times, the adjustment is often done poorly. But poorly adjusted tape causes many problems such as threading problems, threading tail breaks, tape damage and other equipment damage. At the same time there occurs delays in tail threading and the safety issues. The guides contain a lot of specially made parts making production slow and expensive. Also, the existing parts, especially the brackets of the guides are large, heavy, and clumsy. The bracket is attached to the machine frame with bolts. When these bolts are opened, the structure of the bracket falls apart making the adjustment really difficult.

It is an object of the invention to provide a novel guide for a threading tape in a pulp dryer, which guide being easier and faster to adjust than before. The characteristic features of the guide according to this invention are stated in the accompanying Claims. There can be many adjustment directions each one of which can be adjusted independently. Also, the adjustment can be done while the threading tape is under tension and running. Surprisingly, the adjustments can be done with adjustment means that hold against the forces from tape tension and running while enabling precise and fast adjustments.

The invention is described below in detail by referring to the enclosed drawings which illustrate some of the embodiments of the invention, in which.

<FIG> shows a pulp dryer <NUM> including several drying levels arranged on top of each other. Each drying level includes two rows of blow boxes with their nozzle surfaces directed towards each other. When starting the production, a narrow threading tail is cut from the pulp web. The pulp web can be cut with a waterjet cutter before the press section. During the tail threading, the pulp web is run down for pulping. The tail threading is an important and critical event in the startup of the pulp dryer. Failure in the tail threading causes production losses and extra work.

In <FIG>, only the turning rolls <NUM> are shown with one blower tower <NUM>. In practice, there are several blower towers, which supply air to the blow boxes hovering the pulp web (not shown). The righthanded stack of the turning rolls <NUM> has a common drive at the bottom of the pulp dryer. The drying levels with the turning rolls are inside a hood <NUM>. Here, the loop of the endless threading tape <NUM> is also shown. The threading tape runs the same route via the turning rolls as the pulp web during drying. But in the beginning, with several guides the threading tape is first opened, and the threading tail is fed with suitable device or even by hand inside the threading tape. The threading tape closes before the next guide thereby pulling the threading tail inside the hood at the topmost drying level. The threading tape with the threading tail runs through the other drying levels to the lower part of the pulp dryer. At the end, the pulp dryer includes a pull nip <NUM>. After the pull roll <NUM> of the pull nip <NUM>, the threading tape <NUM> returns back forming a closed tape loop while the threading tail continues further (not shown). When the threading tail has proceeded over the first turning roll to the second drying level, the waterjet cutter starts to move sideways. Thus, the threading tail is finally spread out full wide.

As shown in <FIG>, in addition to the turning rolls, the passage of the threading tape is controlled by dozens of different guides, for example pulleys, folding wheels and tape wheels. In general, the guide is for a threading tape in a pulp dryer. Basically, the guides are outside of the hood. Two embodiments of the guide according to the invention are shown in <FIG> and <FIG>. In general, the guide <NUM> includes a wheel <NUM> which is rotatably supported. In other words, the wheel rotates when the threading tape runs. The wheel is supported on an axle <NUM>. Further, the guide <NUM> also includes a bracket <NUM> supporting the axle <NUM>. The bracket is attached on the pulp dryer. There may be also auxiliary supports for attaching each bracket to the pulp dryer. According to the invention, the bracket <NUM> includes two joint points <NUM> and <NUM> for different directions <NUM> and <NUM> each one of which having adjustment means <NUM> and <NUM> respectively of their own. In this way, each direction can be adjusted independently. In practice, even with two direction the most of adjustments can be handled if the guide and its bracket is well positioned at the beginning. Small adjustments are needed, for example when the properties of the threading tape change during its lifetime. With the adjustment means, this fine tuning is quick, easy and accurate. Adjustment is also needed if the pulp web hits the wheel during a web broke. Then the alignment of the wheel may change if the supports bend.

Usually, the threading tape wraps the wheel at least <NUM> degrees, more commonly over <NUM> degrees. Then with two directions <NUM> and <NUM> perpendicular to each other the threading tape can be handled perfectly. It is also easier to choose in which direction the wheel should be turned. Advantageously, the directions <NUM> and <NUM> intersect. In this way, the turnings will change the position of the wheel as little as possible.

This keeps tuning accurate and subtly. At the same time, the forces stressing the bracket keep as little as possible. Also, the geometric features are easy to implement in practice with simple and robust structures.

According to the invention, the adjustment means <NUM> and <NUM> are backlashless. Thus, any harmful vibration is avoided, and adjustment is possible when the threading tape is crawling. In the shown embodiments, the adjustment means includes one or more screws. Also, other spirals or threads may be utilized. With these means, the adjustments are also stepless. Advantageously, the adjustment means <NUM> and <NUM> has locking means <NUM> and <NUM> of their own. In this way, each direction can be adjusted independently. Also, when the tuning is correct, the position can be securely stayed. Next time when the tuning is needed, the locking means are loosened, and adjustment means operated. And finally, advantageously the adjustment means <NUM> and <NUM> and locking means <NUM> and <NUM> are combined or in other way integrated. This makes the structure simple, and it is easy to use with standard tools. Also, any loose parts can be avoided.

<FIG> shows one embodiment of the guide according to the invention. Here, the bracket <NUM> is arranged only on one side of the wheel <NUM>. In this way, it is easy to attach the guide to the pulp dryer. Also, the threading tail can travel without hindrance. Here, the wheel <NUM> is hollow and the joint points <NUM> and <NUM> are arranged inside the circumference of the wheel <NUM>. In this way, the position of the wheel changes as little as possible when the wheel is turned in relation of either direction. At the same time, the forces against the bracket will stay reasonable. And more, the hollow wheel is light weighted, which helps the assembly.

In <FIG>, the bracket <NUM> includes a block <NUM> having a round hole. The hole is for a pin <NUM> with a flange <NUM>. The pin is attached via the flange <NUM> to the pulp dryer or an auxiliary support, and the block is attached to the pin. The block <NUM> and thereby the whole bracket <NUM> with the wheel <NUM> can be adjust both axially and radially in relation to the pin <NUM>. After positioning, the block is secured to the pin. If needed, the guide is afterwards adjusted via the adjustment means according to the invention.

The block <NUM> has two arms <NUM>, one at each side of the block <NUM>. The arms <NUM> are thus at the distance from each other forming a fork. At the inner end of the arms there is the first joint point <NUM>. In relation to this joint point <NUM>, the wheel <NUM> is tilted as shown with dashed lines. To the joint point <NUM> between the arms is attached a shoulder pin <NUM> the upper end of which is connected to the outer end of the arms <NUM> via the first adjustment means <NUM>. Here the adjustment means <NUM> consists of a turnbuckle <NUM>. In both end there is an eye having an inner thread. Between the eyes there is a rod <NUM> with corresponding two-handed outer thread. In the middle of the rod <NUM> there is a key point <NUM>. Here the first locking means <NUM> consist of a nut <NUM> on the rod <NUM>. First the nut is loosened from the eye. Then the rod <NUM> is rotated with a hand tool and thereby the shoulder pin <NUM> and the wheel <NUM> are tilted. The key point can be reached even the wheel rotates. After adjustment, the nut is tightened again.

<FIG> shows a pivot <NUM> which is turnable attached on the shoulder pin <NUM>. The pivot <NUM> also includes the axle <NUM>. More general, the axle <NUM> is attached to the bracket <NUM> and there is a bearing <NUM> between the axle <NUM> and the wheel <NUM>. In other words, the axle is stationary. Here the bearing <NUM> includes two standard ball or roll bearings. Like the arms, the shoulder pin <NUM> is equipped with two lugs <NUM>. The pivot <NUM> has a leg <NUM> situated between the lugs <NUM> like the turnbuckle. In addition, the second adjustment means <NUM> are arranged between the lug <NUM> and the leg <NUM>. Then by urging the leg with the adjustment means the pivot and thereby the wheel are turned. Here also, the adjustment means consist of an inner screw <NUM> with a locking nut <NUM>. Advantageously, there are two opposite screws on both side of the leg.

<FIG> shows another embodiment of the guide according to the invention. Here also, the wheel <NUM> is supported on the axle <NUM> with a bearing <NUM>. In practice, there are one bearing on both ends of the wheel. This this embodiment, the axle is supported by two articulated bearings <NUM> and <NUM> arranged axially apart. In addition, each articulated bearing has a latitude restricted by corresponding adjustment means <NUM> and <NUM>. Here, the outer articulated bearing <NUM> moves sideways while the inner articulated bearing <NUM> moves up and down. The actual turning point of the wheel is outside of the wheel, but the wheel is small, and it has small wrap of the threading tape. Thus, the forces are small.

Basically, both articulated bearings have the same structure, but they have an angle difference of <NUM> degrees. Here, the adjustment means include an adjustment screw <NUM> on one or both sides of the articulated bearing. For clarity, only one adjustment screw <NUM> is shown. Advantageously, there is another adjustment screw on the opposite side. Also, the adjustment screw <NUM> has a nut <NUM> for locking like in the first embodiment. Here, there is an intermediate sleeve <NUM> between articulated bearings. The sleeve with the articulated bearings forms the bracket which is attached to the pulp dryer.

The wheel of the guide according to the invention is supported only on one side. In other words, the bracket is needed only on one side. Nevertheless, the wheel is easily adjustable especially in two directions. As described earlier, the bracket has two basic adjustments. Also, both adjustment ranges are significantly larger than before. In the embodiment of <FIG>, the maximum tilting angle in the direction <NUM> of the threading tape is <NUM> degrees. More generally, the tilting angle is <NUM> - <NUM> degrees. This range is from one end to another. Secondly, in the <FIG>, the maximum turning angle is <NUM> degrees in the other direction <NUM>. More generally, the turning angle is <NUM> - <NUM> degrees. By the new adjustment means, these angles can be changed steplessly and independently from each other. Easier adjustment and better usability are repeated for the entire cycle of the threading tape. Also the ranges are bigger than before. Thus, the auxiliary supports do not have to be made as a tailor made, and one guide fits in various different positions.

Also, the bracket allows transverse adjustment in relation to the machine direction. This possibility is realized with all guides unlike before. The same fastening way also makes it possible to turn the entire structure so that the angle adjustments are always made in accordance with the direction of travel of the threading tape.

Joint points for angle adjustments are near the center of the wheel. In other words, the joint points are inside the circumference of the wheel. This also allows adjustment when the threading tape is running and tight. Also, the weight of the new hollow wheel is about one third of the known wheel. This allows more simpler auxiliary brackets.

<FIG> shows a small wheel with unique adjustment mechanism. More precisely, the adjustment means are implemented with articulated bearings tucked inside the bracket. Here, the maximum adjustment range in each direction is about <NUM> - <NUM> degrees. Again, the adjustment means made screws also allows angle adjustments with the tight threading tape in two directions.

Claim 1:
Guide for a threading tape in a pulp dryer, the guide (<NUM>) including a rotatably supported wheel (<NUM>) on an axle (<NUM>) and a bracket (<NUM>) supporting the axle (<NUM>) and to be attached to the pulp dryer, characterized in that the bracket (<NUM>) includes two joint points (<NUM>, <NUM>) for different directions (<NUM>, <NUM>) each one of which having adjustment means (<NUM>, <NUM>) of their own.