Disc mill sliding head adjustment assembly

Abstract

A disc mill includes: a rotating disc connected to and driven by a shaft to rotate within a housing; and a sliding head plate located within the housing. The sliding head plate has a front surface and a rear surface, and a mill disc capable of non-rotational movement is attached to the front surface of the sliding head plate. An actuator is attached to the housing, and a guide rod support plate is located within the housing. The guide rod support plate has a plurality of spaced-apart guide rod openings. A counterweight is connected to the actuator. The mill also includes a plurality of spaced-apart guide rods, each extending through a corresponding guide rod opening, each guide rod having a first end attached to the rear surface of the sliding head plate and a second end attached to the counterweight. An actuator mounting plate is attached to the housing, and a plurality of tie rods are attached to the actuator mounting plate and the guide rod support plate and extend between them.

Description

Technical Field

[0001] This disclosure relates to a disc refiner including a sliding head that supports a mill disc that can move non-rotationally. Background Technology

[0002] exist Figure 1 In the accompanying drawings, the same reference numerals denote the same components, showing a conventional double-disc mill 20. The mill 20 has a frame 22 on which a rotating assembly 24 is mounted, the rotating assembly having a shaft 26 mounted to a shaft housing 30 via bearings 28. The shaft 26 is connected at its first end 32 to a drive motor (not shown). The second end 33 of the shaft 26 passes through a circular bulkhead 35 at a removable stuffing box 36 and enters the mill housing 34. The second end 33 of the shaft is machined to form a spline 38 on which the hub 40 of the rotor 42 is mounted.

[0003] The drive side 43 of the mill housing 34 has a slurry inlet 44 that supplies slurry to a shroud 46, which defines a triangular cross-section channel between an outer conical shell 48, an inner cylindrical structure 50, and a drive-side stabilizing disc support structure 51. The inner cylindrical structure 50 surrounds a partition 35. The triangular channel allows slurry to enter a slurry chamber formed within the cylindrical structure 50 surrounding the shaft 26. The mill 20 also includes an upwardly extending first outlet 65 for discharging refined pulp.

[0004] The slurry chamber accommodates four refining members or discs, a drive-side non-moving stationary disc 60, a drive-side rotating disc 62, a movable stationary disc 64, and a gate-side rotating disc 66. In the illustrated embodiment, the discs have the same outer diameter. In other embodiments (not shown), only two discs may be used. In still other embodiments (not shown), additional disc sets may be used. In yet another embodiment (not shown), the refining members may be conical or other types of refining members.

[0005] A movable stabilizing disc 64 is mounted on a sliding head 68. The sliding head 68 is mounted to translate toward and away from the rotor 42. The sliding head 68 is mounted via a bearing ring 72 to a removable door 70, which forms part of the mill housing 34. The sliding head 68 is balanced by a counterweight 74 and driven by a screw jack mechanism 76 employing a variable frequency drive motor 78.

[0006] Rotor 42 is mounted on spline 38 at the end of shaft 26. The spline transmits rotational power to the rotor but is not fixed to rotor 42. Sufficient play is provided between rotor hub 40 and spline 38, allowing rotor 42 to slide along spline 38, thereby positioning rotor 42 in response to hydrodynamic forces between a stabilizing disc mounted on support structure 51 and a stabilizing disc 64 mounted on sliding head 68. The spline hub mount is also capable of accommodating very small tilts of the rotor relative to the axis of shaft 26.

[0007] The sliding head 68 supports the door-side stabilizing disc 64 on the support structure 80. This support structure allows slurry to flow behind approximately thirty percent of the outer circumference of the support structure 80, which represents approximately fifty percent of the area of ​​the mill disc 64. Furthermore, due to the pumping action of the rotor 42, the outer thirty percent of the slurry supporting this support structure 80 is under a higher pressure than the slurry flowing through the shroud 46. As the fluid pressure increases radially as the fluid is pumped by the rotor 42, the hydraulic support of the support structure 80 thus supports the highest load portion of the disc. The support structure 80 has a minimal thermal gradient because the disc is directly exposed to the slurry or away from the exterior of the mill 20. Therefore, deflection caused by the thermal gradient is minimized.

[0008] In a mill, the action on the fibers as they pass through the discs requires these discs to be closely spaced, typically between two and four-thousandths of an inch. Maintaining this uniform gap across the entire diameter of the mill discs (which can be fifty-four inches or larger) has historically necessitated the use of massive support structures to resist deflection caused by the pressure between the mill discs.

[0009] By applying slurry pressure to both sides of the stabilizer support structure 80, the flexural load on the support structure 80 is reduced, thereby allowing the use of a lighter support structure with less flexural load.

[0010] The increased rigidity of the stabilizer mounting structure 80, combined with the self-aligning capability of the rotor 42 (the ability to align the rotor itself with the stabilizers 60, 64), results in a more uniform gap between the rotating mill discs 62, 64 mounted on the rotor 42 and the stabilizers 60, 64. The gap between the mill discs is typically between two and four-thousandths of an inch and is usually maintained and supported by the physical thickness of the pulp fibers as they pass between the mill discs. This more uniform gap leads to more even finishing and reduced wear.

[0011] exist Figure 1 In mill 20, the slurry is allowed to be positioned behind the peripheral edge of the stabilizing disc mounting structure, allowing for only a limited degree of equalization of the slurry forces on the mill side. As a result, a considerable force is still required to keep the movable stabilizing disc adjacent to the rotating disc. Summary of the Invention

[0012] A disc mill is disclosed, comprising: a rotating disc connected to and driven by a shaft to rotate within a housing; and a sliding head plate located within the housing. The sliding head plate has a front surface and a rear surface, and a mill disc capable of non-rotational movement is attached to the front surface of the sliding head plate. An actuator is attached to the housing, and a guide rod support plate is located within the housing. The guide rod support plate has a plurality of spaced-apart guide rod openings. A counterweight is connected to the actuator. The mill also includes a plurality of spaced-apart guide rods, each extending through a corresponding guide rod opening, each guide rod having a first end attached to the rear surface of the sliding head plate and a second end attached to the counterweight. An actuator mounting plate is attached to the housing, and a plurality of tie rods are attached to the actuator mounting plate and the guide rod support plate and extend between them. Attached Figure Description

[0013] Figure 1 This is a partial vertical sectional side view of a conventional mill.

[0014] Figure 2 This is a perspective side view of a portion of the mill according to this disclosure.

[0015] Figure 3 for Figure 2 The longitudinal sectional view of the side view of the mill.

[0016] Figure 4 for Figure 2 A partially cut-away three-dimensional side view of the mill.

[0017] Figure 5 for Figure 2 An exploded perspective view of a partially cut-open section of a mill.

[0018] Figure 6 for Figure 2 A sectional view of the mill, taken from the side of the guide rod support plate.

[0019] Figure 7 for Figure 2 A sectional view of the mill, taken from the side of the space between the guide rod support plate and the actuator mounting plate.

[0020] Before detailing one embodiment of this disclosure, it should be understood that this disclosure is not limited to the details of the construction and arrangement of the components set forth in the following description or shown in the accompanying drawings. Other embodiments of this disclosure are possible and it can be practiced or implemented in various ways. Furthermore, it should be understood that the wording or terminology used herein is for illustrative purposes only and should not be construed as limiting. The use of “comprising” and “including” and variations thereof means to cover all items listed thereafter and their equivalents, as well as additional items. The use of “consisting of” and variations thereof means to include only the items listed thereafter and their equivalents. Additionally, it should be understood that terms such as “forward,” “backward,” “left,” “right,” “upward,” and “downward” are words used for convenience and should not be construed as limiting terms. Detailed Implementation

[0021] Figures 2 to 7 A new and improved mill 100 is shown. The mill 100 includes a housing 104 having a portion defining a slurry inlet 108 and a portion defining a slurry outlet 112. (As shown) Figure 2 and Figure 3 As shown, a finishing grinding chamber 116 is located between a slurry inlet 108 and a slurry outlet 112, and a shaft 120 extends into a housing 104. A rotating disk 124 is connected to and driven by the shaft to rotate within the housing 104. A sliding head plate 130 is located within the housing 104 and has a front surface 134 and a rear surface 138. A non-rotationally movable grinding disc 140 is attached to the front surface 134 of the sliding head plate 130. The non-rotationally movable grinding disc 140 is adjacent to the rotating disk 124 such that a small adjustable finishing grinding gap is located between the non-rotationally movable grinding disc 140 and the rotating disk 124. An actuator 144 is attached to the housing 104 to move the sliding head plate 130 relative to the rotating disk 124. The mill 100 improves upon the mill 20 by including a guide rod support plate 150 within the housing 104, and the guide rod support plate 150 has a plurality of spaced-apart guide rod openings. More specifically, in this embodiment, only three guide rod openings 152, 154, and 156 exist (see [link to relevant documentation]). Figure 6 However, in other embodiments (not shown), more openings may be used. The guide rod support plate 150 also serves as an access door for the grinding chamber 116.

[0022] like Figure 3 As shown, counterweight 158 ​​is connected to actuator 144. In this embodiment, counterweight 158 ​​is a circular plate, but in other embodiments, a spoked wheel construction (not shown) and other constructions may be used.

[0023] The mill 100 also includes a plurality of spaced-apart guide rods 160 (see Figure 4 and Figure 6 Each guide rod extends through a corresponding one of guide rod openings 152, 154, and 156, and each guide rod 160 has a first end 162 attached to the rear surface 138 of the sliding head plate 130 (see [link]). Figure 4 The sliding head plate 130 is located on one side of the guide rod support plate 150, and the counterweight 158 ​​is located on the other side of the guide rod support plate 150. In the disclosed embodiment, the three guide rod openings 152, 154, and 156 and the three guide rods 160 are located in a circle spaced apart from the center of the guide rod support plate 150 (see [link to documentation]). Figure 6 ).

[0024] The mill 100 also includes an actuator mounting plate 170 attached to the housing 104, and a plurality of tie rods 180 (see also: [link to housing 104]) attached to and extending between the actuator mounting plate 170 and the guide rod support plate 150. Figure 4 and Figure 7 The actuator mounting plate 170 is spaced apart from the guide rod support plate 150, and a counterweight 158 ​​is positioned between the actuator mounting plate 170 and the guide rod support plate 150. In this embodiment, six tie rods 180 are spaced apart around the periphery of the actuator mounting plate 170, but for smaller or larger mills (not shown), fewer or more tie rods may be used. In other less preferred embodiments, other structural components may be used, such as a cylindrical shell (not shown) attached to and extending between the actuator mounting plate 170 and the guide rod support plate 150.

[0025] The space 184 between the actuator mounting plate 170 and the guide rod support plate 150 is the area containing the bearing 186 and the sensor (not shown), which requires maintenance access. In this design, the removable cover 190 makes it easier than using a small access window in the casting (not shown) of existing designs. The space 184 and the removable cover 190 also prevent dust and debris from the pulp mill from entering the space 184.

[0026] The sliding head plate 130 of this disclosure is exposed to fluid pressure on its rear surface 138, which helps to counteract the fluid pressure applied to the non-rotating mill disc 140. The amount of fluid pressure exposed to the rear surface area is much greater than in conventional designs, where only a very large central piston connects the counterweight to the sliding head plate, such as in... Figure 1The conventional mill shown has a greater amount of rear surface area exposed to fluid pressure, which helps reduce stress on the sliding head plate 130 and the amount of force required to move it. Conventional mills require a large central piston to counteract the forces applied to the sliding head plate. In the disclosed mill, a plurality of spaced-apart guide rods spaced apart from the center of the sliding head plate provide the support needed to counteract the forces shown on the sliding head plate 130.

[0027] Furthermore, in the disclosed mill 100, the various main plates of the assembly (i.e., the door plate, the sliding head plate, and the actuator mounting plate) are held together by guide rods and tie rods, thus eliminating all cast parts and almost all welded parts. The advantage of this type of construction is that it allows for easier removal and repair / reconstruction of all components, including the assembly itself. It also provides modularity in the design, where common components such as guide rods and tie rods can be used for various mill sizes. Finally, it significantly reduces the manufacturing cost and complexity of the sliding head and actuator mechanism compared to conventional methods.

[0028] Various other features and advantages of the present invention will become apparent from the following claims.

[0029] A disc mill includes: a rotating disc connected to and driven by a shaft to rotate within a housing; and a sliding head plate located within the housing. The sliding head plate has a front surface and a rear surface, and a mill disc capable of non-rotational movement is attached to the front surface of the sliding head plate. An actuator is attached to the housing, and a guide rod support plate is located within the housing. The guide rod support plate has a plurality of spaced-apart guide rod openings. A counterweight is connected to the actuator. The mill also includes a plurality of spaced-apart guide rods, each extending through a corresponding guide rod opening, each guide rod having a first end attached to the rear surface of the sliding head plate and a second end attached to the counterweight. An actuator mounting plate is attached to the housing, and a plurality of tie rods are attached to the actuator mounting plate and the guide rod support plate and extend between them.

Claims

1. A disc mill comprising: a housing having a portion defining a slurry inlet and a portion defining a slurry outlet; a refining chamber located between the slurry inlet and the slurry outlet; a shaft extending into the housing; a rotating disc connected to the shaft and driven by the shaft to rotate within the housing; a sliding head plate located within the housing, the sliding head plate having a front surface and a back surface, the sliding head plate exposed to fluid pressure on the back surface; a non-rotatably movable refiner disc attached to the front surface of the sliding head plate, the non-rotatably movable refiner disc adjacent to the rotating disc such that there is a small adjustable refining gap between the non-rotatably movable refiner disc and the rotating disc; an actuator attached to the housing to move the sliding head plate relative to the rotating disc, a guide rod support plate located within the housing, the guide rod support plate having a plurality of spaced apart guide rod openings, a counterweight connected to the actuator, the guide rod support plate serving as a passageway door for the refining chamber, a plurality of spaced apart guide rods, each of the plurality of guide rods extending through a respective one of the plurality of guide rod openings, each guide rod having a first end attached to the back surface of the sliding head plate and a second end attached to the counterweight, the sliding head plate located on one side of the guide rod support plate and the counterweight located on another side of the guide rod support plate, an actuator mounting plate attached to the housing, and a structural assembly attached to and extending between the actuator mounting plate and the guide rod support plate, the actuator mounting plate spaced apart from the guide rod support plate and the counterweight positioned between the actuator mounting plate and the guide rod support plate.

2. The disk mill according to claim 1, wherein, having at least three guide rod openings and at least three guide rods located in a circle spaced apart from the center of the guide rod support plate.

3. The disk mill according to claim 2, wherein, only three guide rod openings and three guide rods located in a circle spaced apart from the center of the guide rod support plate.

4. The disk mill of claim 1, wherein, the counterweight is a circular plate.

5. The disk mill of claim 1, wherein, the structural assembly includes a plurality of tie rods attached to and extending between the actuator mounting plate and the guide rod support plate.

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