JPH03211155A - Web guide mechanism - Google Patents

Abstract

PURPOSE: To correct dislocation without damaging a web by detecting existence of an edge with a single sensor installed adjacent to one edge of the web, and adjusting the spacing of pinch rollers on both sides of the web using an actuator depending upon the result from detection. CONSTITUTION: Route deciding units 10 and 40 are installed on the sides of a web, and one sensor 58 is installed adjacent to one of the web edges so that detection is made whether any web exists. The units 10 and 40 are equipped with a pair of rollers 12 and 14 and ones 42 and 44, respectively, and thereby the web is held pinchedly. The pinching force depends upon the air injection amount to bellows 28 and 48. When the web in traveling is dislocated aside to cause the sensor 58 to judge out of web, a control valve 52 is actuated to send air to that actuator on the side where the web is biased (for example, 48) so as to strengthen the pinching force of the rollers, and the dislocation is eliminated. Thus web dislocation can be corrected simply, and the web is free of risk being damaged.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a web guiding mechanism, and more particularly to a mechanism for guiding a web of filter fabric material in a continuous belt filter.

BACKGROUND OF THE INVENTION In known continuous filter devices, the filter element is usually an endless belt made of porous material, which is placed around end pulleys as a belt filter, or by means of a rotating vacuum (suction). ) placed partially around the suction drum as a belt filter. These belts of filter material must be guided or routed so that they run through the center of the equipment to prevent tangling and other machine malfunctions. Such a course is also essential to ensure that the fabric material itself is not damaged during use.

Generally known methods for making such career decisions include:
A pair of nip rollers are used and are arranged at an angle of approximately 10" to the range of belt travel. The nip rollers are normally open or engaged and the fabric sensor is They are placed on both sides of the cloth so that the movement of the edge of the cloth relative to its normal path can be detected.

For normally open rollers, the sensor is activated by movement of the edge of the fabric towards it, which causes the nip roller to close on the opposite side of the material and
The web is pulled back against the actuated sensor to allow normal navigation. In systems where the nip rollers are normally closed, actuation of one or more sensors causes the rollers to open, thereby causing the fabric web to move in the opposite manner as previously described. In most of these systems, the sensor and nip roller are mounted in one common unit.

The web guidance mechanisms described above have largely evolved from technology in the textile industry, where similar guidance controls are required during rolling and other manufacturing operations. Such systems work best when the fabric web is guided only once, so that the extent of damage caused to the edge of the fabric by the nip rollers is of no consequence.

In continuous belt filters, the filter cloth runs for many months between replacements and therefore passes through nip rollers and other guiding mechanisms many times (perhaps hundreds or tens of times).
00 times).

Therefore, any excessive strain exerted on the filter cloth by these mechanisms will significantly weaken the surface structure, leading to damage and unreliable filtration properties.

Furthermore, most known filter fabrics tend to stretch during use to the extent that the width of the fabric narrows slightly. This requires frequent sensor reorientation to cope with it. Failure to perform such redirection may result in excessive movement of the fabric, thereby requiring excessive force on a portion of the mechanism to pull the fabric back onto the correct course. If the web is misaligned too much, the steering mechanism may not be able to pull the fabric back to the center position. Furthermore, if the sensor and nip roller are provided as one unit, the nip roller must also be re-routed when the sensor re-route, and for this purpose the nip angle (usually 10° as mentioned above) is This may change during the decision making process. Yet another problem associated with the unique properties of filter fabrics is that they tend to form wrinkles and creases. To prevent this, it is effective to always apply a slight tension to the cloth, especially before passing under the reversing roller.

It is therefore an object of the present invention to provide a web guiding mechanism that senses the position of the web and its deviation from its desired course, corrects the deviation without damaging the web material, and that also adapts to the properties of the filter fabric. The object of the present invention is to provide a particularly suitable web guiding mechanism.

[Means for Solving the Problems] In order to achieve the above object, the web guiding mechanism according to the present invention has one of the webs on or adjacent to the desired course of the edge, and the web guide mechanism on the desired course of the web on the desired course. A single sensor is provided for detecting the presence or absence of an edge, two steering units are placed on either side of the web path, and each steering unit is provided with a pair of rollers between which the web is moved. forming a nip space through which each edge of the roller passes, and each path determining unit is provided with an actuator that adjusts the position of one roller relative to the other, thereby opening and closing the nip space between the rollers. a single sensor is connected to each navigation unit such that either one or the other actuator selectively operates as described above depending on whether the presence or absence of a web is detected. characterized in that it is actuated by a single sensor to close the pinch spaces of the corresponding pairs of rollers, thereby pinching the corresponding edges of the web and displacing the web to its lateral side; It is said that

In an embodiment, each actuator includes an inflatable element that acts on one of each pair of rollers.

The web guiding mechanism according to the invention further comprises sensor means arranged to detect the presence or absence of one or both edges of the web, and two steering units arranged on either side of the web, one for each steering unit. a pair of rollers are provided to define a sandwich space between the rollers through which each edge of the web passes; an actuator is provided in each steering unit, the actuator adjusting the position of one roller relative to the other; The sensor means is thereby operative to open and close the nip space between the rollers, and the sensor means is connected to each path determining unit, thereby controlling one or the other depending on whether the presence or absence of the web is detected. Either of the actuators is selectively actuated by the single sensor to close the pinch space of the corresponding pair of rollers, thereby pinching the corresponding edges of the web so that the web is pulled to its lateral side. each actuator comprises an inflatable element.

It is advantageous if the sensor means are connected to the navigation unit via switching means.

It is also preferred to mount the sensor means at a location remote from the path determining unit, and it is advantageous to mount the web on or adjacent to a generally vertical portion of the desired path.

It is advantageous to connect the inflatable element to a source of compressed gas.

The invention will be explained by means of illustrated embodiments.

[Embodiment] FIG. 1 shows one course determining unit and an actuator attached thereto according to an embodiment of the present invention. One course determining unit 10 includes an upper roller 1
2 and a lower roller 14, both rollers 12.14
are supported by bearings so that they are parallel to each other. The lower roller 14 is supported by a bracket 16 via a bearing, and is movable relative to the upper roller 12.

The bracket 16 itself is pivotally connected to a support frame, which also supports the upper roller 12. Bracket 16 is formed of two end plates 20 with an axis or bar 24 disposed therebetween generally parallel to the respective axes of rotation of upper and lower rollers 12.14. A contact plate 26 is attached to the bar 24.
is seated on an inflatable actuator 28 formed by an inflatable bellows. Preferably, the bellows is made of rubber, PTFE, nylon or other materials that are resistant to corrosion and contamination. The bellows may be in the form of a balloon, and preferably has bellows on the sides and an elongated upper surface. Additionally, the bellows 28 has a large diameter and volume, e.g.
Preferably, the height is 8° in mm. In order to raise the lower roller 14 correctly, the bellows 28 must be centered on the roller 14. The bellows should also extend as wide as possible over the length of the roller so that the motion of the roller 14 is generally perpendicular to the axis of rotation of the upper roller.

In such a construction, the rollers 12,14 forming the steering unit 10 can be moved towards each other using very low pressure and the speed of actuation can be precisely controlled. - The above operation is clearly different from the movement of the steering unit of a fishing textile machine, which is very fast and can cause damage to the textile material. Although the bellows described above is most suitable using air as the inflation medium, other gases and liquids may also be used.

The method of operation of the bellows 28 is as shown in FIG. FIG. 2 schematically shows a web guiding mechanism according to the invention. Two steering units 10.40 are shown in FIG. 2, each unit 10.40 having an upper roller 12.
．． 42 and a lower roller 14.44. 1 each
The paired rollers are supported as shown in FIG. Each steering unit 10.40 is associated with an actuator 28.48 formed by bellows, which are connected to a compressed air source 50 via a control valve 52.

Operation of the control valve 52 is controlled by an actuation valve 54 which is connected to a fabric sensor 58 via a trip switch 56. A fabric sensor 58 is mounted to detect one edge of the web of material passing therethrough. In continuous belt filter machines, fabric sensor 5
8 is preferably attached at a point where the filter cloth is generally vertical, because the stability of the edge relative to the cloth sensor 58 is high in the vertical running section. The reason for such high stability is that the distance between the reversing rollers, which reverse the direction of movement of the fabric, is relatively small and therefore the edge that the sensor detects is relatively stable in this respect. be.

Activation of trip switch 56 by sensor 58 actuates activation valve 54 to switch control valve 52, thereby directing air from air source 50 to one or the other bellows 28.48. The direction of movement of the cloth relative to the sensor 58 determines which bellows 28.48 are inflated to effect the closing of each respective pair of rollers 10.40 and the pinching action of the filter cloth passing therebetween. Both the control valve 52 and the actuation valve 54 are provided with a spring return mechanism 53.55 for returning each valve 52.54 to its original position.

The cloth sensor may be activated either when there is a cloth edge running against it or when there is no cloth edge.
Accordingly, the movement of the trip switch 56 and the control of the actuation valve 54 are set such that little filter cloth deflection occurs during operation. Even if the filter cloth stretches during use, the negative edge will still travel within the detection range of the cloth sensor 58, causing the cloth to move slightly off center on its desired path; However, at no point can any edge of the fabric swing towards the drive roller and associated sharp parts and cause damage to the fabric.

A further advantage of the invention is that the pressure on one or the other of the bellows 28.48 can be released relatively slowly and the pressure on the other bellows 28.48 can be increased relatively slowly. be. In this way, it is possible to gradually change from closing one pair of rollers (10, 40) to closing the other pair of rollers, while maintaining a gentle tension over the entire width of the fabric to filter the filtration. Wrinkles and folds, which are detrimental to the operating properties of the device, can be prevented.

4.Although the illustrated embodiment uses a pneumatic (pressurized air) control device, the same principle may be used to control the actual expansion of the bellows 28.48 using electrical or optical signals or hydraulic equipment. The movement can be controlled.

Of course, the above embodiments are for explaining the present invention, and the present invention is not limited thereto, and various modified structures can be adopted.

For example, additional cloth sensors may be provided to more closely limit the position of the cloth within a particular desired path. The actuation and control valves can be of any type depending on how the control device is actuated and how the bellows 28.48 is inflated. Several pairs of rollers can be placed at suitable locations along the desired path of the fabric and can be controlled individually or by a single sensor. The sensor does not have to be attached to the vertical run; it can also be mounted to the horizontal run if this is more convenient.

Although the present invention is particularly applicable to continuous belt filtration equipment,5 its unique advantages can also be utilized in textile machines to provide accurate routing of fragile fabrics, and to provide accurate routing during rolling processes. It can also be used where career decisions are required. Preferably, the control and actuating valves are standard pneumatic valves, such as those commonly available commercially.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of an embodiment of the invention, and FIG. 2 is a schematic diagram of the route determining unit and control means according to the invention. DESCRIPTION OF SYMBOLS 10... Route determination unit, 12. 14... Roller, 16... Bracket, 28... Bellows, 40...
...Route decision unit, 42.44...Roller, 5
0... Pressurized air source, 52... Control valve, 54...
・Operation valve, 58...sensor

Claims (1)

Claims: 1. Providing on one of the webs, on or adjacent to the desired path of the edge, a single sensor for detecting the presence or absence of the edge of the web on said desired path; two course determining units are arranged on both sides of the web course, each course determining unit is provided with a pair of rollers to form a sandwich space between the rollers through which each edge of the web passes; each course determining unit is provided with an actuator operative to adjust the position of one roller relative to the other, thereby opening and closing the sandwich space between the rollers, and the actuator is operable to adjust the position of one roller relative to the other, thereby opening and closing the sandwich space between the rollers; unit, whereby either one or the other actuator is selectively actuated by said single sensor depending on the presence or absence of the detection of the presence or absence of a web, thereby causing the pinching of the corresponding pair of rollers. A web guiding mechanism characterized in that the space is closed so that corresponding edges of the web are clamped and the web is displaced to its side. 2. The guide mechanism of claim 1, wherein each actuator includes an inflatable element acting on one of each pair of rollers. 3. The guide mechanism according to claim 1, wherein the sensor is mounted at a location remote from the course determining unit. 4. A guide mechanism according to claim 3, wherein the sensor means is mounted on or adjacent the portion of the desired path in which the web is generally vertical. 5. Sensor means arranged to detect the presence or absence of one or both edges of the web, two steering units arranged on either side of the web, each steering unit provided with a pair of rollers to detect the presence or absence of one or both edges of the web; A nip space is formed between the rollers through which each edge of the web passes, and each steering unit is provided with an actuator that adjusts the position of one roller relative to the other to thereby eliminate the nip space between the rollers. operative to open and close the space, said sensor means being connected to each navigation unit such that either one or the other actuator is selectively activated depending on whether the presence or absence of a web is detected. is actuated by said single sensor to close the pinch spaces of the corresponding pairs of rollers, thereby pinching the corresponding edges of the web and forcing the web to its lateral sides, so that each Web guiding mechanism, characterized in that the actuator comprises an inflatable element. 6. A guiding mechanism according to claim 5, wherein the sensor means is connected to the route determining unit via switching means. 7. The guide mechanism of claim 5, wherein the inflatable element is connected to a source of compressed gas. 8. A guide mechanism according to claim 5, wherein the sensor means is mounted at a location remote from the course determining unit.