US3908880A

US3908880A - Method and apparatus for regulating the motion of a web

Info

Publication number: US3908880A
Application number: US503074A
Authority: US
Inventors: Gerd Russmann; Hans Fauser
Original assignee: JM Voith GmbH
Current assignee: JM Voith GmbH
Priority date: 1973-09-18
Filing date: 1974-09-04
Publication date: 1975-09-30
Anticipated expiration: 1992-09-30

Abstract

A method of and a device for regulating the motion of a web, particularly for maintaining the web in a certain path within predetermined lateral limits. The device comprises a nozzle for directing a jet in the substantially vertical direction toward the region where one edge of the web moves whereby the web when in normal position intercepts a portion of the jet. A receiver on the opposite side of the web from the nozzle intercepts the portion of the jet which passes by the web and converts the energy of the jet into static pressure. The nozzle and receiver are mounted on a support which moves in the lateral direction of the web in conformity with the static pressure developed in the receiver. A control system under the influence of the static pressure or, under the influence of the moveable support, actuates a guiding device for the web and the web is, in this manner, smoothly and accurately regulated as to the lateral position thereof along the web path.

Description

United States Patent 1191 Riissmann et al.

1 1 Sept. 30, 1975 l l METHOD AND APPARATUS FOR REGULATING THE MOTION OF A WEB [73] Assignee: J. M. Voith, GmbH, Heidenheim.

Germany 221 Filed: Sept. 4, 1974 1211 Appl.No.:503,074

[30] Foreign Application Priority Data Septv 18, 1973 Germany 2345821 [52] US. Cl. 226/3' 226/7; 226/19; 226/22; 226/45; 73/37.7 [5]] Int. CL" B65H 25/26 [58] Field of Search 226/3, 7. 19, 22. 45; 73/377; 137/82 [56] References Cited UNITED STATES PATENTS 2.735 630 2/l956 Ziebolz 226/22 UX 334L099 9/1967 Jacobsen... 226/19 3.509.794 5/1970 Allen 226/19 X Primary Etumincr-Richard A. Schacher Attorney, Agent, or Firm-Melvin A. Crosby [57] ABSTRACT A method of and a device for regulating the motion of a web particularly for maintaining the web in a certain path within predetermined lateral limits. The device comprises a nozzle for directing a jet in the substantially vertical direction toward the region where one edge of the web moves whereby the web when in normal position intercepts a portion of the jet. A receiver on the opposite side of the web from the nozzle intercepts the portion of the jet which passes by the web and converts the energy of the jet into static pressure. The nozzle and receiver are mounted on a support which moves in the lateral direction of the web in conformity with the static pressure developed in the receiver. A control system under the influence of the static pressure or, under the influence of the moveable support. actuates a guiding device for the web and the web is, in this manner. smoothly and accurately regulated as to the lateral position thereof along the web path.

16 Claims, 3 Drawing Figures US Patent Sept. 30,1975 Sheet 1 of2 3,908,880

U.. Patent Sept. 30,1975 Sheet 2 of2 3,908,880

METHOD AND APPARATUS FOR REGULATING THE MOTION OF A WEB Thepresent invention relates to a method and apparatus for regulating the motion of a web, especially a papermachine wire or felt, or the like, in which thee regulation is accomplished smoothly at all times and with a strength which is generally proportional to any lateral displacement of the web.

The 'present invention is concerned with a method and apparatus of the nature referred to above which employs a scanning device which scans one edge of the web being regulated. The scanning device is in the form of a jet of fluid, advantageously liquid, which is discharged from a nozzle on one side of the web and which is intercepted by a receiver disposed on the other side of the web.

The receiver converts the energy of the jet into static pressure with the degree of the static pressure being in conformity with the amount of the jet which is intercepted by the edge of the web. A control mechanism is provided which includes a guiding means for the web and the control means, including the guiding means, is moveable under the influence of the aforementioned static pressure whereby the web is subjected to guidance. V

7 A particular feature of the present invention is that the nozzle] and receiver are moveably amounted adjacent the edge of the web and are also moveable in unison under the influence of the static pressure so that the control influences developed thereby do not vary erratically but are continuous and vary with the amount of lateral movement of the web and the web is thereby accurately maintained in a predetermined path of movement. I v

It is known from the West German Pat. No. 747,717 to provide an installation with two scanning devices which employ liquid jets and which jets are intercepted by a receiver. The liquid is guided to the pan of a to a pair of nozzles, one of which, depending upon the position of the balance, will direct a jet upon a bucket wheel or impeller to effect rotation thereof. When the impeller rotates, a web guiding roll is adjusted. In this manner, by reversible rotation of the bucket wheel or impeller, the web can be caused to be adjusted in the lateral direction.

The referred to installation of West German Pat. No. 747,717 is not only rather bulky, but the operation thereof is attended with considerable difficulty, especially when employed with a wide machine. When the device of the patent is utilized with a wide machine, there are rather long connection conduits required from the receiver to the scale, or balance. Because of such long connections, the adjusting mechanisms exhibits a rather high inertia and is slow in operation. Such an arrangement is, of course, not at all acceptable in respectof modern high speed machines.

In still another West German Pat. No. 1,008,106, another device of generally the same type as that above referred to is disclosedand wherein twoscanningdevices are provided which operate with liquid jets. One scanning device is provided at each side of the web and the devices are housed in a common constructional unit. If the web is located between the two liquid jets, no adjusting of the web position will occur. Only when both jets are intercepted by the web, or when both are fully uncovered by the web, will the lateral position of the web become adjusted.

In an installation of this nature, the web may oscillate in the lateral direction, but with short webs, such as short paper machine wires, which run rapidly, oscillationof this nature is simply not permissable. Furthermore, neither of the installations referred to above can be operated without careful preliminary adjustment.

In still another West German Pat. No. 960,956, an installation is disclosed-in which the edge portion of a web is scanned, or felt mechanically, and such an installation, at least in theory, would be capable of regulating and adjusting any deviation of the web from a predetermined path substantially immediately. It is the case, however, that such an installation cannot be employed with rapidly moving webs such as rapidly running wires, felts, or similar units, because the mechanical friction of the scanning of feeler means at the edge of the web wears rapidly at high web velocities and can quickly become "ineffective.

With the foregoing in mind, a primary object of the present invention is the provision of a method and apparatus of the nature referred to which avoids the difficulties which have been encountered with devices according to the prior art.

A further object is the provision of a simple but highly effective method and apparatus for regulating the position of a travelling web in a continuous manner and while avoiding oscillation of the web.

BRIEF SUMMARY OF THE INVENTION According to the present invention, there is provided a nozzle for establishing a fluid jet, preferably, a liquid jet, which moves in a direction generally perpendicular to the plane of movement of a web and near the edge of a web. On the opposite side of the web is a receiver which intercepts the jet and which converts the velocity energy of the jet to a static pressure.

The nozzle and receiver are mounted on a common support which is moveable transversely to the direction of movement of the webfThecommon support is urged in one direction by anexpansible element which receives static pressure from the receiver and is urged in the opposite direction by a return spring acting in the opposite direction.

The return springisadjusted to the pressure generated in the receiver so that when the jet passing from the nozzle to the receiver becomes'partially intersected by the web, the pressure created in the receiver by the remaining portion of the intersected jet will become exactly'balanced by the tension of the return spring. N

If, under these balanced conditions, the web moves in the lateral direction, then either more or lessof the jet will be intercepted by the web and the aforementioned balanced conditions will no longer prevail. This change of the balanced conditions brings about that the common support will move in the direction of travel of the web and will carry with it the nozzle supplying the jet and the receiver until a balanced condition is again established. x

The movement of the support itself may initiate a control operation for adjusting the position of the web or, the pressure developed in the receiver can be employed for this purpose, either directly or with amplification.

From the foregoing, it will be seen that, according to the present invention, an adjustment tending to correct the position of the web is obtained which is generally proportional to the error in the motion of the web. Because of this, the greater the error in web motion the greater will be the return force which acts upon the web. The web is thus strongly urged toward a predetermined position and this is accomplished without actual engagement of the web and without any hunting or oscillation of the web.

. The exact nature of the present invention and the various objectives and advantages thereof will become more apparent upon reference to the following detailed specification taken in connection with the accompanying drawings in which:

,FIG. 1 is a somewhat schematic view, partly in perspective, showing the web position detecting device according to the present invention and mounted on a moveable support members.

FIG. 2 is a schematic drawing showing the principle of operation of the device and wherein the changes in the static pressure at the receiver are employed for initiating the adjustment of the position of the web.

FIG. 3 is a view similar to FIG. 2 but wherein the movement of the support member which supports the nozzle and receiver is employed for initiating the control function.

DETAILED DESCRIPTION OF THE INVENTION Referring to the drawings somewhat more in detail,

reference numeral 1 indicates the web to be controlled. What is shown is a machine wire for a paper making machine but any type of web, such as a felt, could be guided according to the present invention. It is desired to guide the web, or wire, in a predetermined path without' lateral deviation of the web in the plane in which it is moving. [According to the present invention, a scanning device is located at a lateral edge of the web and includes a nozzle 2 which directs a fluid jet 4 to a receiver, generally indicated at 5. The fluid jet is preferably a water jetand the nozzle 2 is, accordingly, connected by conduit 3 to a source of water under pressure.

The receiver 5 is mounted on the upper end of a conduit 6 which extends downwardly and then into one end of a fluid expansible device 7 which may, for example, be in the form of a bellows. One end of device 7 abuts a stationary member 8, whereas the other end abuts a rocking lever 9, which is pivotally supported on member 8 at the lower end of lever 9. The aforementioned nozzle and receiver are connected to lever 9 to move therewith and are positioned above the upper end. of lever 9 so as to be able to receive the edge of web 1 therebetween.

A tension spring 10 biases the upper end of lever 9 toward the right in the contrasting direction of fluid expansible device 7 and is adapted for fine adjustment by means of screw 11.

In the adaptation of the scanning device of FIG. 1, reference may be had to FIG. 2 wherein it will be seen that receiver 5 is connected via a pressure sensitive device 12 to a component 13 which produces a standardized signal. This signal is supplied to a regulator 14 which is adapted for reversibly supplying fluid under pressure to an adjusting cylinder 15. Cylinder 15 is connected to a pivotally supported arm 17 on the upper end of which is rotatably mounted a guide roll 16.

The arm 17 extends downwardly beyond the pivotal support for the arm and has a feedback connection to the regulator 14 so that a feedback of the control motion of the guide roll is provided. It will be understood that the nozzle 2 and receiver 5 illustrated in FIG. 2 are of the nature illustrated in FIG. 1, wherein the nozzle and receiver are mounted on a common support and move laterally of the web in response v,to pressure changes in receiver 5. v

Turning now to FIG. 3, and wherein the scanning device is shown in its entirety and with the same reference numerals applied thereto in FIGS. 1 and 2, the lever 9 which supports the nozzle and receiver is extended downwardly below its pivotal connection with stationary member 8 so as to present an arm portion 9'. Arm portion 9 is connected to the moveable member of a valve structure 18.

Valve structure 18 is supplied by

conduits

19 and 20 and the valve member which is moved'by arm portion 9 is so constructed that movement thereof will reversibly vary the connection of conduitsl9 and 20 with exhaust passage 21. Thus, as the valve member moves to the left, the connection of conduit 20 to exhaust passage 21 .is restricted, while the connection of conduit 19 with exhaust passage 21 is made more freel If the valve member moves in the opposite direction, the reverse effect takes place. i I

The guide roll 16 is, as in connection with FIG. '2,

mounted on a tiltablelever and connected to the lever is a reversible fluid motor 22 which may include bias springs acting in opposite directions on the piston thereof. Conduits 24 and 25-are provided for supplying fluid underpressu re, in this case, compressed air, and these compressed air lines are connected through fluid amplifiers 23 to the opposite ends of motor 22. Pressure is supplied to

conduits

24 and 25 from a supply conduit 27 via respective restrictors 26 Conduits l9 and 20 are connected to

conduits

24 and 25 between restrictors 26 and fluid motor 22. I

Depending on the particular position of the valve member of regulating valve 18, the pressure is varied in the opposite ends of motor 22 and in this manner an adjustment of the position of guide roll 16 occurs tending to return web, or wire, 1 to the desired lateral position thereof. i

In every case, with each of the described modifications, if the web l moves laterally from a predetermined position, the portion of the jet coming from the nozzle 2 and intercepted by the receiver 5 will vary and this will not only initiate a control function to bring about an adjustment of the lateral position of the wire, but will also cause the support of the jet and receiver to move in the direction that the wire moved from the starting position thereof.

Any time that the support member for the nozzle and receiver moves, however, a change will occur in the tension of the return spring acting on the support mem-' her. The inherent tendency of the arrangement is always to return to the same position with the nozzle and receiver following the motion of the wire but moving a smaller amount than the wire moves. Stable equilibrium conditions in respect ofthe nozzle and receiver will thus be established in only one predetermined lateral position of the web, or wire, and in which position a certain predetermined portion of the jet from the nozzle to the receiver will be intercepted by the web, or wire.

As has been seen, the variation in pressure in the receiver can be employed for initiating the adjustment of the position of the wire, but it is also the case that the motion of the support member for the nozzle and the receiver can initiate the adjustment of the position of the wire.

The influence tending to restore the web to the desired position thereof will be seen to be generally proportional to the amount of lateral movement of the web. The restoring influence does not, at any time, change extremely rapidly and, because of this, there is no tendency for the web to oscillate or hunt.

Modifications may be made within the scope of the appended claims.

What is claimed is:

1. Apparatus for regulating the movement of a web, such as a paper machine wire which comprises first means for supplying a fluid jet from one side of the plane of the web in a direction generally perpendicular to the plane of the web and at the edge of the path of the web whereby the edge of the web intercepts a portion of said jet, a second means on the other side of the plane of the web disposed to intersect the remaining portion of said fluid jet and convert the energy thereof to a static pressure, a common support supporting said first and second means and moveable laterally to the path of the web, resilient means biasing said support in one direction of movement thereof, fluid operable means connected to said support for movement of the support in the opposite direction of movement thereof and connected to receive said static pressure from said second means, guide means engaging said web and adjustable for controlling the path of the web, and control means for actuating said guide means in conformity with one of the movement of said support and the variations in static pressure at said receiver.

2. Apparatus according to claim 1 in which said fluid of said jet is a liquid.

3. Apparatus according to claim 1 in which said support is a pivotally supported lever.

4. Apparatus according to claim 1 in which said support is a lever pivotally supported near one end and having said first and second means connected thereto near the other end.

5. Apparatus according to claim 1 in which said fluid operable means is an axially expansible bellows element having one end engaging said support and the other end stationarily supported.

6. Apparatus according to claim 1 in which said guide means includes a guide roll engaging the web, a fluid motor connected to the guide roll for adjustment thereof, and said control means being operated by movement of said support for reversibly supplying fluid to said motor.

7. Apparatus according to claim 6 in which the amount of movement imparted to said guide roll by said control means is substantially proportional to the amount of movement of said support.

8. Apparatus according to claim 6 in which said fluid motor is double acting and which includes a source of fluid under pressure, respective restrictions connecting said source to opposite sides of said motor, a respective exhaust passage leading from each side of said motor, and valve means in said exhaust passages connected to said support for movement in conformity therewith and operable for reversibly restricting said passages.

9. Apparatus according to claim 1 in which said control means comprises a fluid controller operable for reversibly controlling the supply of fluid to said motor, and means responsive to variations in static pressure at said receiver for actuating said control means.

10. Apparatus according to claim 1 in which said control means comprises a fluid controller operable for reversibly controlling the supply of fluid to said motor, and means responsive to variations in static pressure at said receiver for actuating said control means which includes feed back means actuated by movement of said guide roller and connected to said fluid controller.

11. The method of controlling the lateral position of a longitudinally moving web which comprises; arranging a nozzle for supplying a jet and a receiver for receiving the jet and for converting the energy thereof to static pressure on opposite sides of the web at one side edge of the web so the web partly intercepts the jet from the nozzle, providing a common support member for the nozzle and jet which is moveable in the lateral direction of the web, detecting changes in static pressure at the receiver from a predetermined normal pressure in said receiver when the web is in a desired position and intercepts a predetermined portion of the jet, moving the support member in respective directions laterally of the web in response to changes in said static pressure in respective senses from normal pressure as brought about by lateral movement of the web, and simultaneously initiating a control influence on the web tending to move the web in the lateral direction opposite to the direction of movement of the support member.

12. The method according to claim 11 in which said support member is biased in one direction by a spring and is biased in the other direction by a fluid operable expansible device sensitive to said static pressure.

13. The method according to claim 12 in which the bias of said spring on said moveable member varies in direct porportion to the displacement of said member.

14. The method according to claim 13 which includes adjusting said spring to adjust the normal position of the web in the lateral direction.

15. The method according to claim 11 in which said control influence is initiated by changes in said static pressure from the normal pressure.

16. The method according to claim 11 in which said control influence is initiated by movement of said support member.

Claims

2. Apparatus according to claim 1 in which said fluid of said jet is a liquid.