Refiner disc and hub assembly

An assembly comprising an annular hub with a hub inner surface and a hub outer surface and a rotary third refining member having a central opening within a refining member inner surface. The refining member has at least two equally spaced apart member portions extending radially inwardly from the member inner surface, and the assembly includes a key for connecting the member portions to the hub. The assembly also include an annular cover plate with at least two radially extending spaced apart flanges, each flange overlying a member portion, and at least two spaced apart port plates, each port plate overlying a member portion side opposite the annular cover plate, the spaces between the at least two port plates defining ports from a first stock flow path to a second stock flow path.

BACKGROUND

The present disclosure relates to refiners for wood pulp or the like, and more particularly to improvements in refiners wherein stationary refining plates flank rotary refining plates in the chamber of a housing whose inlet admits stock for treatment by comminuting projections (e.g., ribs) on the neighboring surfaces of stationary refining plates and rotary refining plates.

It is already known to utilize in a disc or rotor refiner two coaxial or eccentric plates or discs each of which is driven by a discrete prime mover and which have neighboring surfaces provided with ribs or otherwise configured projections which comminute the material to be treated while the material advances from the inlet toward the outlet of the stock chamber. It is further known to use a pair of discs one of which is stationary and the other of which rotates relative to the stationary disc.

It is also known to dispose two rotary discs between two stationary discs so that each rotary disc cooperates with a different stationary disc. The rotary discs are mounted at the opposite sides of a disc-shaped carrier which is driven by a shaft. The stock is fed through one of the stationary discs to enter the space between the one stationary disc and the respective rotary disc, and some of the stock is allowed to pass through relatively small openings in the rotary discs to enter the space between the other rotary disc and the other stationary disc.

The openings though the rotary disc are usually sized for high stock flow. In some instances, however, lower stock flow is required. In this instance, too much stock can flow through the rotary disc and thus cause unequal flow on both sides of the disc. In conventional applications, an annular ring has been added to the inlet side of the rotary disc to reduce the size of the openings. This annular disc adds to the weight of the rotary disc and further reduces the flow area through the inlet stock passageway. The annular disc also covers portions of the rotary refining member other than the ports, thus adding further unnecessary metal and weight to the refining member. It has also been known to weld plates over a portion of the ports in order to reduce the port sizes.

A better approach to allow for adjustment of the stock flow openings is needed.

SUMMARY

Disclosed is an assembly comprising an annular hub with a hub inner surface and a hub outer surface and a rotary third refining member having a central opening defined by a refining member inner surface. The refining member has at least two equally spaced apart member portions extending radially inwardly from the member inner surface, and the assembly includes a key for connecting the member portions to the hub. The assembly also include an annular cover plate with at least two radially extending spaced apart flanges, each flange overlying a member portion, and at least two spaced apart port plates, each port plate overlying a member portion side opposite the annular cover plate, the spaces between the at least two port plates defining ports from a first stock flow path to a second stock flow path.

Before one embodiment of the disclosure is explained in detail, it is to be understood that the disclosure is not limited in its application to the details of the construction and the arrangements of components set forth in the following description or illustrated in the drawings. The disclosure is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. Use of “including” and “comprising” and variations thereof as used herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Use of “consisting of” and variations thereof as used herein is meant to encompass only the items listed thereafter and equivalents thereof. Further, it is to be understood that such terms as “forward”, “rearward”, “left”, “right”, “upward” and “downward”, etc., are words of convenience and are not to be construed as limiting terms.

DESCRIPTION OF AN EMBODIMENT

Elements in Common with the Prior Art

Referring first toFIG.1, there is shown a prior art disc refiner having a housing10including several bolted-together sections two of which are shown at12and14. The description ofFIGS.1through5comes from one such prior art construction, as shown in Pilao U.S. Pat. No. 3,984,057. The housing defines a stock chamber16and has an inlet18for admission of pulp, e.g., from the outlet of a pump, a first outlet20for evacuation of refined pulp, at least in part under the action of centrifugal force, and a second outlet22which is normally closed by a suitable valve24. The outlet20extends upwardly and the outlet22extends downwardly; the valve24is opened when the attendants wish to drain the liquid carrier for wood chips or the like from the chamber16.

The chamber16accommodates a first refining member26, a second refining member30, and a third refining member28, here shown as coaxial discs having identical outer diameters. In other embodiments (not shown), two back-to-back discs can be used instead of the single disc28. In still other embodiments (not shown), additional disc sets can be used. In still other embodiments (not shown), the refining members may constitute cones or other types of refining members.

The disc26is stationary and is fixedly secured to the housing section12by screws32or analogous fasteners. The disc30does not rotate. This disc is spaced apart from the disc26and is secured to an axially movable support34by means of screws36or the like. The support34is mounted in the housing section14and is movable axially of the discs26,28by a reversible electric motor38which can drive a worm40. The latter meshes with a worm wheel42having internal threads in mesh with external threads at the right-hand end of a spindle44which is rigid with the support34. The support34has one or more radial projections or followers46slidable in elongated grooves48of the housing section14. The grooves48are parallel to the common axis of the discs26,28and30. In other embodiments, other mechanisms for supporting the disc30can be used.

The disc28is rotatable relative to and is movable axially between the discs26and30. The means for rotating the disc28comprises a drive shaft50which rotates in a sleeve52in the housing section12. The sleeve52is surrounded by a stuffing box54which prevents the escape of pulp from the chamber16into the left-hand portion of the housing section12. That end portion of the shaft50which extends from the housing section12preferably carries a pulley or sprocket wheel driven by an electric motor or another suitable prime mover through the medium of an endless belt or chain. Other types of transmissions between the prime mover and the shaft50can be used with equal advantage.

The disc26has a relatively large central opening56which communicates with the inlet18and surrounds the shaft50with a substantial amount of clearance. That end portion of the shaft50which extends beyond the opening56and into the central part of the chamber16carries a hub58which is secured thereto by a key60, a cap62and a screw64so that the hub58shares all angular movements of the shaft50. The hub58transmits torque to the centrally located disc28by way of several screws66but the disc28has limited freedom of axial movement relative to the hubs58and screws66. The hub is provided with an eccentric blind bore68for a torque transmitting guide pin70, a portion of which extends into an aligned blind bore72of the disc28. It can be said that the disc28“floats” between the discs26,30and automatically finds a central position between the stationary discs26,30, not only in response to wear on the surfaces of comminuting projections on the discs but also upon axial adjustment of the disc30.

The discs26,28and28,30respectively define first and second paths P1and P2along which the pulp can advance from the inlet18toward the first outlet20(the second outlet22is assumed to be sealed when the refiner is in use). The path P1is flanked by rib-shaped comminuting projections74,76of the discs26,28, and the path P2is flanked by rib-shaped comminuting projections78,80of the discs28,30. The opening56of the disc26admits pulp from the inlet18into the central portion of the first path P1, and such pulp flows radially outwardly between the projections74,76toward the outlet20. The central portion of the disc28, as shown inFIG.2, has three kidney-shaped openings82whose combined cross-sectional area is less than the effective area of the opening56. The openings82connect the path P1with the path P2so that some of the pulp which is admitted via opening56flows through the openings82and into the path P2to be comminuted by the projections78,80on its way toward the outlet20. The openings82are partially separated from each other by radially inwardly extending portions84one of which has the blind bore72and each of which has one or more untapped bores86for the respective screws66.

FIG.4shows a portion of the disc26which may be identical with the disc30. The diameter of the opening56in the disc26is about one-half the outer diameter of this disc. The effective area of the opening56is that area of this opening which surrounds the corresponding portion of the shaft50. The combined effective area of the openings82in the disc28is smaller than the effective area of the opening56because the disc28receives the hub58and also because this disc is formed with the portions84. However, the combined effective area of the openings82is large enough to ensure that the quantity of pulp which flows from the openings82into the path P2is identical or practically identical with the quantity of pulp flowing from the opening56into the path P1.

FIG.5shows the prior art hub58. This hub has a keyway59for the key60and three radially outwardly extending arms61which overlie and are secured to the portions84of the disc28. One of the arms61has the bore68for a portion of the guide pin70and each arm has at least one tapped bore63for the stem of the respective screw66.

The Improved Assembly

As illustrated inFIGS.6and7, an improved assembly100according to this disclosure replaces the disc28and hub58ofFIGS.1through5with an improved third refining member or disc126, hub158, an annular cover plate102, at least two spaced apart port plates104and106. In the preferred embodiment, the annular cover plate102and the hub158are an integral one piece.

In one embodiment, the improved assembly100further includes attaching means adapted to attach the hub to the drive shaft including a collar110.

The hub158is adapted to be rigidly connected to the drive shaft50and received in a third refining member central opening130so that the third refining member126is movable axially along the shaft50, and the rotary third refining member126has a central opening130within a refining member inner surface136(seeFIG.8). As illustrated inFIG.8, the rotary third refining member126has at least two equally spaced apart member portions140and144extending radially inwardly from the member inner surface136. In a preferred embodiment, there are three equally spaced apart member portions140,144and148.

The improved assembly100further including connecting means for connecting the member portions140,144and148to the hub158, the connecting means comprising the annular cover plate102with at least two radially extending spaced apart flanges152and156(seeFIG.9), each flange overlying a member portion, and the at least two spaced apart port plates104and106(seeFIG.10), each port plate overlying a member portion side opposite the annular cover plate102. In a preferred embodiment, there are three equally spaced apart port flanges152,156and157and three equally spaced apart port plates104,106and108. In other less preferred embodiments (not shown), the spacing between the three port flanges need not be equal. The connecting means ensures the refining member126rotates with the hub158and the hub158remains in place on the refining member126.

In one embodiment, the connecting means comprises each member portion having a portion key notch160(seeFIG.8), a hub outer surface162having a hub keyway164(seeFIG.10), and a key166received in each portion key notch160and each hub keyway164.

Each port plate is secured in place relative to its respective member portion, and the spaces between the at least two port plates define spaced apart ports170,172and174(seeFIG.7) from the first path to the second path. More particularly, in one embodiment, a pair of threaded bolts182and184pass through the cover plate102, through corresponding openings in the member portion and into a threaded opening in the port plate, so that the cover plate, the member portion, the key, and the port plate together form a connected assembly100.

In one embodiment, the attaching means comprises a spline on the hub inner surface185, and the annular collar110having an outer surface188with a spline to engage the spline on the hub inner surface185. The annular collar110also has an inner surface186with a collar keyway189for attachment to a key (not shown) engaging the drive shaft50. In other less preferred embodiments, a spline or a keyway and key can be used in the alternative, and the collar and hub can be made as one piece.

Also disclosed is a method for using the improved assembly100, the method comprising the steps of defining a first size of the ports170,172and174through the assembly100by providing a first port plate104(seeFIG.13) with a length which defines a first port size, and defining a second smaller size of the ports through the assembly100by providing a second port plate104′ (seeFIG.14) with a longer length. An even smaller size port is possible with an even larger port plate104″ (seeFIG.15). If port plates of both sizes are provided to a refiner customer, the customer can choose a port plate size appropriate based on the amount of stock flow the refiner is expected to experience in order to best equalize the stock flow on both sides of the refining member. Larger port plates will result in more stock in flow path P1, while smaller port plates will result in less stock in flow path P1.

This method provides substantial less additional metal than in the prior art without adding a further obstruction to the stock flow path between the third refining member and the other refining members.

The port plates also affect the direction of the flow path through the refining member. Different port plate shapes (not shown) can also be used to provide different flow path directions through the refining member.

Various other features and advantages of the invention will be apparent from the following claims.