US2855829A - Paper making machine - Google Patents

Description

Oct. 14, 1958 M. ALLEMANN PAPER MAKING MACHINE Filed June 22, 1955 2 Sheets-$heet 1 INVENTOR.

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/f. 14 ATTO/F/VEK Oct. 14, 1958 M. ALLEMANN PAPER MAKING MACHINE Filed June 22, 1955 2 Sheets-Sheet 2 INVENTOR. MART/N ALLEMA/wv. BY {4 W,

ATTORNEK United States Patent PAPER MAKING MACHINE Martin Allemann, Winterthur, Switzerland, assignor to Sulzer Frres, Socit Anonyme, Winterthur, Switzerland, a corporafion of Switzerland Application June 22, 1955, Serial No. 517,185 Claims priority, application Switzerland June 23, 1954 11 Claims. (Cl. 92-47) The present invention relates to a machine for making lengths of paper or cellulose including means for drawing liquid from the pulp or paper mat, and including at least one blower or compressor. The pulp or paper mat is supported by an endless wire screen belt in the wet end of the machine, the belt forming a loop and having an upper run whose end is adjacent to the dry end of the machine for transferring the paper mat to the dry portion of the machine. A suction roller is provided at the aforementioned end of the screen belt and outside of the loop formed by the belt. The suction roller is normallyadjacent to the screen belt, but can be lifted away from the belt for selectively allowing the paper mat to remain on the belt, until the belt moves from the upper run to the lower run, whereupon the paper mat or pulp drops from the belt into a container, or for lifting the paper mat from the belt for transferring it to the dry portion ofthe machine.

The object of the invention resides in the provision of means for automatically lifting the aforesaid suction roller from the belt whenever an undesired operating condition occurs in the machine. Such an undesired operating condition may be an increase of the pressure in any one of the suction devices through which water is drawn out of the wet pulp or paper mat, rendering the suction device inoperative and necessitating stoppage of the machine and transfer of the pulp or paper mat from the endless screen belt in the wet portion of the machine into a container from which the mass can be returned to a reservoir from which it is again placed on the screen belt. Such a condition prevails particularly if the pressure in a suction roll which is adjacent to the screen belt and inside of the loop formed thereby increases so that the pulp or paper mat is insufficiently or not at all dried and is still wet when it approaches the ing to the invention prevents damage to the screen belt caused by such accumulationsor, congestion of the wet mass, for example tearing of the screen belt or undesired stretching and permanent deformation of the screen belt resulting in unduly large meshes. I

In an embodiment of the invention, a device is provided for lifting the suction roller which is normally on top of the upper run of the loop formed by the screen belt (henceforth called the outside roller), which device is actuated upon an undesired pressure in a suction roll adjacent to the screen belt and inside of the loop formed by the screen belt (henceforth called the inside roll). The outside suction roller is lifted upon a predetermined increase of the suction pressure in the inside suction roll which increase may be caused by failure of the blower or its drive, or leakage in the conduit-connecting the blower with the inside suction roll.

2,855,829 Patented Oct. 14, 1958 ice The outside roller may be connected with a piston reciprocatively movable in a cylinder which is supplied with a pressure fluid whose flow is controlled by a valve actuated in dependence on the pressure in the inside suction roll. A bellows is preferably arranged whose interior communicates with the interior of the suction con'duit connected with the inside suction roll. The aforesaid valve is operated by means of a solenoid which is interposed in an electric circuit which is controlled by a mercury tumbler switch, the latter being actuated by the aforesaid bellows.

In another modification of the invention, the blower is driven by an electric motor and the outside suction roller is lifted away from the screen belt if'themotor driving the blower becomes inoperative, for example because of lack of electric current. In this case, the lifting mechanism becomes operative immediately upon failure of current supply to the motor, i. e. before the (slowly rising) pressure in the suction conduit connected with the blower reaches a point when the lifting mechanism would be actuated by a device responsive to the suction pressure in the inside suction roll.

In a third, modification of the invention, the current supply to the electric motor driving the blower is interrupted when the water level in a water separator interposed in the suction conduit connecting the blower with the insidev suction roll reaches a predetermined elevation and the lifting mechanism for the outside roller is actuated when the current supply to the motor is interrupted In this case, thelifting mechanism is actuated at the moment at which the motor is stopped, in contradistinction to arrangements inwhich the lifting mechanism is actuated by the rising suction pressure, i. e. much later than when the motor is stopped.

The lifting mechanism is preferably so arranged that the mechanism for interrupting the current supply to the motor simultaneously actuates the lifting mechanism.

In an embodiment of the invention, the water separator forms an electric condenser vwhose capacity is used for simultaneouslyactuating the lifting mechanism and cutting out the current supply to the electric motor driving the blower. The arrangement is particularly reliable because rests of pulp or paper, which may be in the water in the separator and which impede the reliable operation of mechanical means responding to the water level in the water separator, have no influence on the functioning of the water separator as an electric condenser. In this case, the metallic casing of the condenser forms one electrode of the condenser and an insulated rod extending into the casing above the maximum water level therein forms the other electrode. The water in the condenser forms the dielectric and the capacity of the condenser depends on the water level in the water separator. The condenser forms part of an alternating current circuit in which the intensity of the current corresponds to the water level inthe water separator. The current may be amplified by means of'a conventional amplifying arrangement. A relais is interposed in the aforedescribed circuit. Therelais is actuated at a predetermined intensity of the current in the circuit and simultaneously actuates, bysuitable conventional means, a device for interrupting the current supply to the motor driving the blower and a device for actuating the lifting mechanism for the outside roller. Since the relative dielectric constant of water is very great, approximately 81, the last described system for the combined actuation of the lifting mechanism and the device for stopping the motor is sufficiently sensitive.

The novel features which are considered characteristic of the invention are set forth' with particularity in the appended claims. The invention itself however and addi- 3 tional objects and advantages thereof will best be understood from the "following description "of embodiments thereof when read in conjunction with the accompanying drawing, in which- 'Fig. l is a schematic illustration of a part "of ap'aper makingmachine according to'the invention; 7

Fig. 2 is "a diagrammatic sectional view of 'a device used in the machine shown in Fig. 1;

Fig. 3 is a diagrammatic sectional illustration'of another device usablein connectionwith the plant'shown in Fig.1; p

Fig. '4is a diagrammatic illustration of 'a third device which may beused in connectionfwith the plant shown in "Fig. 1.

The same numerals designatethesameparts' in all figures.

Referring more particul'arly'to Fig. 1 of the drawing, numeral 23 'design'ates an endless screen band or belt which is usually woven of copper wire, and which supports the pulp or mat of'paper 24. Only the portion of the screen belt is shownwhich is adjacent to the dry part of the machine which is at the right of the belt 23. The screen band is. guided by a suction or couch roll 21 and is looped around a roller 22. The pulp or paper continue to'moveto a dry portion of the machine, of which a part is shown at the right side of Fig. 1. The "pulp or paper 24 is carried through the dry portion of the machine by means of a belt 96 movingbetween roller pairs 25, 26 and 27, 28. A pressure roller 29 and a suction roller 30, the latter being adapted to lift the pulp or paper from the screen band, facethe outside of the screen band. The pressure roller 29 can be lifted upwardly from the screen band by means of'a'hydraulic or pneumatic piston device 96, 98 and the suction roller 30 can be lifted upwardly from-the screen band by means of a hydraulic or penurnatic piston device 97, 99.

The suction'roller 21, the paper lifting roller 30, and the pressure rollers 25 and 27 are connected by means of suction conduits-31 to 35, 36 to 38, and 39 to 41 with a blower 43 which is driven by an alternating current m'otor42. The conduits 35, 38, and 41 are connected to different stages of the blower, so that the different desired suctionpressures will prevail in these conduits and parts connected therewith. A primary water separator 46 is interposed between the conduits 33 and 34, and a secondary water separator 49 is interposed between the conduits 34 and 35. A primary water separator 47 is interposed between the conduits 36 and 37, and a secondary water separator 50 is interposed between the conduits 37 and 38. A primary water separator 48 is interposed between the conduits 39 and 40 and a secondary water separator 51 is interposed between the conduits 40 and 41. The water separators take away the water which has been removed from the pulp 24. In the diagram Fig. 1, the secondary "separators are shown high above the main separators. In the actual plant, the secondary water separators are preferably located close to the primary separators. No safety head'need be provided in the suction conduits between the main separators and the blower, since the latter is provided with an automatic cutout which will be described later. The water separated in the main separators 46 to 48 is removed by pumps 52 to 54, respectively. Whenever the water level in a primary water separator reaches a predetermined maximum elevation, a switch 65 interposed in the conduits 64 supplying the motor 42 with electric energy is opened by means of control devices 55 to 57 which will be described later. The control devices 55, 56, and 57 are individually attached to the primary separators 46, 47, and 48, respectively. The control pulse generated in the device 55 is conducted by means of a conduit 58 to a common conduit 61, and therefrom to the switch 65. The control pulse generated in the device 56 is conducted to the common conduit'61 by means of a conduit 59. The control pulse generated in the device 57 is conducted by means of a conduit 60- to the common control pulse conduit 61. The devices 55 to 57 are also adapted to energize solenoids 69 and to which they are connected by suitable means 66, 67, and 68, the means 66 being connected to the common conduit means 61. The solenoids 69 and 70 actuate valves 71 and 72, respectively, which valves control the flow of the operating fluid through conduits 73 and 74, respectively, to the devices 96, 9'8 and 97, 99, respectively. Valves 75 and 76 which are suited for manual operation are arranged in. pipe lines by-passing the valves 71 and 72, respectively. Pressure fluid is supplied through a valve 77, which is manually operated, to the four valves 71, 72, 75, 76. At normal operation, i. e. when there is not more water in any of the primary separators than is desired, the valves 71 and 72 are held in closed position by means of the energized solenoids 69 and 70, respectively. The pistons 96 and 97 and the rolls 29 and 30 are inthe illustrated lower position, due to gravity. The roll 29 presses the mat ofpaper against the wire screen belt 23, whereas the roll 31 lifts the mat of paper from the belt 23 for transferring the mat of paper to the press portion 'of the machine. If the water level in one of the separators 46 to 48 rises above the maximum permissible elevation, the switch 65 which is actuated by a solenoid 62 is opened and the solenoids 69 and 76 are deenergized, opening the valves 71 and 72 and supplying a pressure fluid, for example compressed air, into the cylinders 98 and 99 below the pistons 96 and 97, respectively, for lifting the pistons and therolls 29 and 38 connected thereto. The mat of paper which is not dried by the roll 21 and other rolls, which are not shown, after the blower 43 has been stopped by opening the switch 65, can now continue to rest on the belt 23, because it is not lifted by the roll 30 and can be guided below the lifted rolls 29 and 30 until it reaches the roller 22, whereupon it drops into a container, not shown. The material may then be brought into a main reservoir from which it is again returned to the process.

Fig.2 illustrates a device which is suitable to form the control devices 55 to 57. The device is described in connection with the separator 46. However, it is the same for the separators 47 and 48. The casing 12 of the separator 46 is grounded at 13. An electrically insulated horizontal rod 9 extends through an aperture 14-inside of the separator casing 12. The electric insulation 15 of the rod 9 inside of the casing 12 is acid and lye resisting and made, for example, of polyvinylchloride. The rod 9 is grounded'through a relais 17 and a source of alternating current 16, so that the rod 9 and the casing 12 form an electric condenser which is interposed in the auxiliary circuit 18 formed by a spool corresponding to the spool 199 shown in Fig. 4 which will be described later, the source 16, the ground, and the conduits interconnecting these elements. The spool which forms part of the relais 17 actuates a switch also forming part of the relais 17 and being interposed in a main electric circuit in which also the solenoid 62 actuating the switch 65 and the solenoids 69 and 70 for operating the valves 71 and 72, respectively, are interposed. A rising water level in the casing 12 changes the geometric conditions of the condenser and consequently its capacity so that also the intensity of the alternating current in the circuit 18 is changed. At a predetermined water level, the spool of the relais -17 is sufiiciently energized to open the switch controlling the main electric circuit so that the solenoid 62 is deenergized and the switch 65 is opened causing stopping of the blower 43, and the solenoids 69 and 70 are deenergized causingopening of the valves 71 and 72 and lifting of the rolls 29 and 30 from the wire screen belt 23.

In a plant according to Fig. 1 in which the switch 65 maybe actuated manually or automatically, i. e. which may not or may include the elements 55 to 61, a mercur tumbler switch illustrated in Fig. 3 may be connected with'th'e suction conduit 31. The switch 80 includes a. closed glass container 82 adapted'to rock on pivot 81 and containing mercury 83, which, in the position shown, connects the contacts 84 and 85. The latter are interposed in the circuit formed by the conduits 66 to 68' and the solenoids 69 and 70. The container 82 is connected by a linkage 86, 87 with bellows 88, the in terior of which communicates'through a conduit 89 with the conduit 31. When the switch 80 is'in the illustrated position, the solenoids 69, 70 are energized and the valves 71 and72 are closed, so that the rolls 29 and 30 are in the illustrated lower or active position. There is normal operating pressure in the conduit 31 and in the bellows 88, so that the paper mat is relatively dry when it passes under the roller 30. If the pressure in the conduit 31 is too high, the bellows is expanded, pushing the rod 87 downward and swinging the container 82 counterclockwise in Fig. 3 so that the electric connection between the contacts84, 85 is interrupted. The solenoids 69 and 70 are deenergized and the valves 71 and 72 are opened so that the pressure fluid, for example compressedair, moves the pistons 96 and 97 upwards.

In anothermodification of the invention, the plant shown in Fig. 1, in which the switch 65 may be actuated manually or automatically, i. e. which may not or may include the elements 55 to 61, the solenoids 69 and 70 are connected with a source 93 of low tension electric current by means of conduits 90 and 91, as shown in Fig. 4. A switch 92 is interposed in the conduit 90. The switches 92 and 65 are operated by a relais whose coil 94 is interposed in a circuit 198 receiving current from the source 93 and including a switch 197. The latter is actuated by a coil 199 which is interposed in a secondary circuit 18 of a transformer 100. The primary part of the transformer 100 is interposed in the high tension supply lines 64 for the motor 42-. When there is no alternating current in the conduits 64, the coil 199 is deenergized and the switch 197 is opened, so that the coil 94 is without current and the switches 65 and 92 are opened. The solenoids 69 and 70 are therefore deenergized, the valves 71 and 72 are opened and the rolls 29 and 30 are lifted away from the screen belt 23.

While specific embodiments of the invention have been shown and described, it will be apparent to those skilled in the art that various changes, modifications, substitutions, additions and omissions may be made therein without departing from the spirit and scope of the invention as set forth in the appended claims.

What is claimed is:

1. A paper making machine including an endless screen belt forming a loop and having an upper run supporting the wet mat of paper, a suction apparatus including at least one blower and a suction device placed adjacent to said screen belt, conduit means interconnecting said device and said blower, a roller disposed outside of the loop formed by and being normally adjacent to said screen belt, lifting means connected with said roller for removing said roller from said screen belt, and actuating means connected with said lifting means for actuating said lifting means, said actuating means including means responsive to an operating condition of the machine causing a rise of the pressure in said suction apparatus beyond a predetermined limit for activating said actuating means.

2. A paper making machine as defined in claim 1, in which said actuating means include means responsive to the suction pressure in said suction apparatus for actuating said lifting means upon an excessive pressure in said suction apparatus.

3. A paper making machine according to claim 2, said lifting means including a cylinder, a piston reciprocatively movable in said cylinder and connected with said roller,

pressure fluid supply means connected with said cylinder for supplying a pressure fluid thereinto for moving said piston and said roller connected therewith, and a valve in said pressure fluid supply means for controlling the supply of pressure fluid to said cylinder.

4. A paper making machine as defined in claim 1, said lifting means including a cylinder, a piston reciprocatively movable therein and connected with said roller, pressure fluid supply means connected with said cylinder for supplying a pressure fluid thereinto for moving said piston and said roller connected therewith, a valve interposed in said supply means for controlling the supply of pressure fluid to said cylinder, said actuating means including an electric circuit including a solenoid connected with said valve for actuating said valve, a tumbler switch interposed in said circuit, and a bellows whose interior communicates with said conduit means, said bellows being connected with said tumbler switch for opening the latter upon excessive pressure in said conduit means and deenergizing said solenoid for actuating said valve.

5. A paper making machine as defined in claim 1, in-' cluding an electric motor for driving said b1ower,electric conduit means for supplying electric current to said motor, said actuating means including means responsive to the flow of current in said electric conduit means for actuating said lifting means upon an interruption of the supply of electric current to said motor.

6. A paper making machine according to claim 5, said lifting means including a cylinder, a piston reciprocatively movable in said cylinder and connected with said roller, pressure fluid supply means connected with said cylinder for supplying a pressure fluid thereinto for moving said piston and said roller connected therewith, and a valve in said pressure fluid supply means for controlling the supply of pressure fluid to said cylinder, said means responsive to the flow of current in said electric conduit means being connected with said valve for operating said valve.

7. A paper making machine as defined in claim 1, including an electric motor for driving said blower, electric conduit means for supplying current to said motor, said lifting means including a cylinder, a piston reciprocatively movable therein and connected with said roller, pressure fluid supply means connected with said cylinder for supplying a pressure fluid thereinto for moving said p1ston and said roller connected therewith, a valve interposed in said supply means for controlling the supply of pressure fluid to said cylinder, said actuating means including an electric circuit including a solenoid connected with said valve for actuating said valve, said actuating means including a relais responsive to the flow of current in said electric conduit means and being associated with said switch for opening said switch upon an interruption of the supply of electric current to said motor and for deenergizing said solenoid for actuating said valve.

8. A paper making machine as defined in claim 1, including a water separator interposed in said conduit means, said drive means including an electric motor, electric conduit means for supplying electric current to said motor, a switch interposed in said electric conduit means, said actuating means including means responsive to the water level in said water separator and being connected with and adapted to actuate said switch and said lifting means when the water level in said separator reaches a predetermined elevation.

9. A paper making machine according to claim 8, said means responsive to the water level in said water separator including an auxiliary circuit of electric alternating current in which an electric condenser is interposed, said electric condenser being formed by said water separator, the latter including a metallic casing forming one electrode of the condenser, an electrically insulated rod extending into the said casing above the maximum desired water level in the separator and forming the other electrode of the condenser, the water in the separator forming the dielectric of the condenser, and a relais interposed in said auxiliary circuit and including a solenoid adapted to be energized upon a predetermined electric capacity of the condenser, which capacity is determined by the water level in said casing, said actuating means including electrically operated means for actuating said switch and said lifting means, said relais including 'a switch formingpart of said electrically operated means and adapted to be actuated by said solenoid.

10. A paper making machine according to claim 8, said means responsive to the water level in said water separator including an auxiliary circuit of electric alternating current in which an electric condenser is interposed, said electric condenser being formed by said water separator, the latter including a metallic casing forming one electrode of the condenser, an electrically insulated rod extending into the said casing above the maximum desired water level in the separator and forming the other electrode of the condenser, the water in the separator forming the dielectric of the condenser, and a relais interposed in said auxiliary circuit and including a first solenoid adapted to be energized by a predetermined electric capacity of the condenser, which capacity is determined by the water level in said casing, said lifting means including a cylinder, a piston reciprocatively movable in said cylinder and connected with said roller, pressure fluid supply means connected With said cylinder for supplying a pressure fluid thereinto for moving said piston and said roller connected therewith, a valve interposed in said supply means for controlling the supply of pressure fluid to said cylinder, said actuating means including a main electric circuit, a second solenoid interposed in said main circuit for actuating said switch, a third solenoid interposed in said main circuit for actuating said valve, said relais including a switch adapted to be actuated by said first solenoid and interposed in said main circuit for controlling energization of said second and third solenoids.

'11. A paper making machine including an endless screen belt forming a loop and having an upper run supporting the wet mat of paper, a suction device including at least one blower and one suction roll inside of the loop formed by and being adjacent to said screen belt, conduit means interconnecting said suction roll and saidblower, a roller disposed outside of the loop formed by and being normally adjacent to said screen belt, lifting means connected with said roller for removing said roller from said screen belt, drive means for said blower, means for interrupting said drive means, and actuating means connected with said lifting means and with said drive means for coordinating said drive means and said lifting means to lift the latter whilst said drive means are interrupted.

References Cited in the file of this patent UNITED STATES PATENTS 2,264,168 Poirer Nov. 25, 1941 2,340,103 Berry Jan. 25, 1944 2,415,351 Hornbostel Feb. 4, 1947

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