Abstract
A comminution device for laboratory operation is described. More specifically, a laboratory mill, particularly a centrifugal mill, is provided that includes a milling tool arranged in a milling chamber, a housing assembly, and a milling material channel running through the housing assembly. The milling material channel opens into the milling chamber and is configured to supply, for supplying milling material to the milling chamber or to discharge milled material from the milling chamber. The milling material channel may be open to the environment and/or can be opened for successively supplying milling material to the milling chamber during the milling operation. At least one system for passively reducing noise emissions is provided and situated in the region of the milling material channel.
Claims
1. A comminuting device for laboratory operation, comprising; a milling tool arranged in a milling chamber; a housing assembly associated with the milling chamber, the housing assembly having a housing wall that forms a milling material hopper; a milling material channel that extends through the milling material hopper into the milling chamber; wherein the milling material channel is adapted to supply milling material to the milling chamber or remove milling material from milling chamber when the milling material channel is open to the environment for a successive supply of milling material to the milling chamber during a milling operation; at least one damper inserted into the milling material hopper and arranged in the area of milling material channel for passive reduction of noise emissions by at least partial reflection of noise from cross-sectional changes in the at least one damper, directional changes in the at least one damper, or a combination thereof; and wherein the at least one damper has a proximal portion having a first opening associated with the milling chamber and a distal portion having a second opening opposite the proximal portion, and wherein a cross-sectional geometry of the proximal portion corresponds with a cross-section geometry of the milling material hopper of the comminution device.
2. The comminution device according to claim 1, wherein the first opening of the at least one damper corresponds with an inlet of the milling chamber, and wherein the distal portion of the at least one damper forms a funnel geometry that defines a material inlet for milling material.
3. The comminution device according to claim 1, wherein the at least one damper is closed on a shell side.
4. The comminution device of claim 1, wherein the first and second opening are arranged coaxially, and wherein the first opening has a larger cross-section than the second opening.
5. The comminution device of claim 1, wherein the at least one damper is configured to accept milling material feed from a direction other than parallel to a central longitudinal axis of the at least one damper.
6. The comminution device of claim 1, wherein the at least one damper in a distal direction has at least a constant or discrete cross-sectional change, the at least one damper cross-section in the distal direction being constant from a proximal end of the damper through the proximal portion and increasing constantly to the distal portion.
7. The comminution device of claim 1, wherein the at least one damper at its distal portion has at least one directional deflection for sound in the radial direction to a central longitudinal axis of the at least one damper or in the proximal direction to the milling chamber.
8. The comminution device of claim 1, wherein at least one sealing means is provided between the at least one damper and the milling material hopper.
9. The comminution device according to claim 1, wherein the at least one damper is integrated into the housing assembly and associated with the milling material channel.
10. The comminution device according to claim 1, wherein the distal portion comprises an inwardly extending neck, such that the second opening is located below an outermost extent of the distal portion.
11. The comminution device according to claim 10, further comprising a toroidal insulation member situated between an outside surface of the inwardly extending neck and an inner surface of the distal portion.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) FIG. 1 is a longitudinal section view of a first embodiment of a damper designed and provided as a separate device part for use in a comminution device for laboratory operation,
(2) FIG. 2 shows the damper of FIG. 1 with the arrangement of a sound-absorbing material inside the damper,
(3) FIG. 3 inserts the damper of FIG. 1 into a milling material channel of a centrifugal mill,
(4) FIG. 4 inserts the damper shown in FIG. 2 into the milling material channel of the centrifugal mill shown in FIG. 3,
(5) FIG. 5 is two dampers of the type shown in FIG. 1 in a longitudinal section view, where the two dampers are extended into each other,
(6) FIG. 6 is a longitudinal section view of another embodiment of a damper designed and provided as a separate device part for use in a comminution device for laboratory operation,
(7) FIG. 7 is a longitudinal section view of a third embodiment of a damper designed and provided as a separate device part for use in a comminution device for laboratory operation,
(8) FIG. 8 inserts the damper from FIG. 7 into the milling material channel of a centrifugal mill,
(9) FIG. 9 is a laboratory mill with a damper arranged above a milling material hopper of the laboratory mill in a schematic sectional view.
DETAILED DESCRIPTION
(10) FIG. 1 shows a muffler 1 as a separate device part for use in a comminution device 2 for laboratory operation, for example as shown in FIGS. 3 and 4. The comminution device 2 is, for example, a centrifugal mill as shown. The basic structure of the comminution device 2 can correspond to the basic structure of the centrifugal mill described in EP 0 727 254 A1. The damper 1 is designed for passive reduction of noise emissions emanating from a milling chamber 3.
(11) As shown in FIGS. 3 and 4, the comminution device 2 has a rotor 5 coupled to a drive shaft 4 as milling tool, where the milling chamber 3 of rotor 5 is surrounded by an annular sieve 6 and on the outer circumference of the annular sieve 6 an annular collection container 7 is arranged for the crushed milling material. The collection container 7 is covered with a container lid 8. The milling unit consisting of rotor 5, annular sieve 6 and collection container 7 can be closed with a housing lid 10 having a milling material inlet opening 9.
(12) The milling material feed into the milling chamber 3 occurs through a milling material hopper 11, which is formed by a wall of the housing lid 10 and forms or borders a milling material channel 12 of the comminution device 2. The milling material channel 12 is connected with the milling material inlet opening 9 and therefore with the milling chamber 3. The milling material channel 12 is open to the environment during the milling operation. This enables a successive feed of the milling material to the milling chamber 3 during the milling operation.
(13) To house the comminution device 2 at least one housing 13 is additionally provided, which can also be designed in multiple parts. The closure downward is formed by a base plate 14.
(14) For passive reduction of noise emissions, the muffler 1 shown in FIG. 1 and FIG. 2 can be inserted into the milling material hopper, preferably detachably. This is shown in FIG. 3 for damper 1 from FIG. 1 and in FIG. 4 for damper 1 from FIG. 2. Damper 1 is des signed for passive reduction of noise emissions by reflection of sound from cross-sectional and/or directional changes in damper 1. For this, damper 1 is brought into the sound path between milling chamber 3 and the external air surrounding comminution device 2. Barriers are placed in the way of the sound waves in damper 1 so that they are thrown back and diverted. The sound waves partially cancel each other out. Various cross-sections of damper 1 lead to sound reflection and therefore sound reduction. The reduction of noise emissions through damper 1 attributable to damper 1 is at least 10 dB(A), preferably at least 20 dB(A), particularly preferably at least 30 dB(A) relative to a non-damped operation of comminution device 2.
(15) As emerges in particular from FIGS. 1 and 2, the milling material is supplied to milling chamber 3 through damper 1. The milling material channel 12 correspondingly runs through damper 1 and is bordered on the outside by damper 1. The transport of material through damper 1 is shown schematically by arrows 15 in FIG. 1.
(16) The damper 1 is closed on the shell side and the front side at its lower, proximal end 16 and at its upper, distal end 17 each has a central opening 18, 19. The outlet opening 18 and inlet opening 19 are arranged coaxially in the embodiment shown. The outlet opening 18 preferably has a larger cross-section than the inlet opening 19.
(17) Damper 1 can have a wall designed as one part or multiple parts with a proximal shell or damper portion 20, a distal shell or damper portion 21 subsequent to it distally, and a distal head portion 22. For an effective sound reduction the clear damper cross-section going from the proximal end 16 of damper 1 in the distal direction can be constant over the proximal damper portion 20 and steadily increase in the subsequent distal damper portion 21.
(18) At the head portion 22 and distal end 17 of damper 1 is provided an inner surface 23, which causes a directional deflection for sound in the radial direction toward the central longitudinal axis 1 of damper 1 and in the axial direction toward milling chamber 3. This results in directional deflection of the sound waves in the area of the distal end 17 of damper 1, as schematically shown in FIG. 1 by arrow 24. There is also reflection of sound waves from the inner surface 23. With multiple passes through the interior of the damper 1, a reduction of sound pressure peaks is thus achieved.
(19) The proximal damper section 20 comprises on the inside a cylindrical shell surface 25, which transitions to a conical shell surface 26 in the distal damper portion 21. The distal damper portion 25 is followed by the head portion 22, the distal inner surface 23 of which is curved or angled relative to shell surface 26 of distal damper portion 21 in the radial direction toward the central longitudinal axis Y. In the area of opening 19 of distal end 17 of damper 1, the inner surface 23 can then be curved or bent or angled inward in the proximal direction, also conical. This creates a funnel geometry at distal end 17 of damper 1, which forms a funnel neck 27, which extends relative to the distal end 17 of damper 1 proximally into the interior of damper 1. The distal inner surface 23 in the longitudinal section has approximately the contour of a semicircular torus.
(20) As is apparent from FIG. 2, damper 1 in the area of head portion 22 can have an inside insulation 28 of a sound-absorbing material. Preferably, the insulation 28 is provided at the distal end 17 of damper 1 in the area between funnel neck 27 and the outer wall of damper 1. Thus, the damper 1 also acts as an absorption muffler containing a porous material, such as rock wool, glass wool, glass fibers or foams, which partially absorbs the sound energy, i.e. converts it into heat. The sound absorption effect can be enhanced by the multiple reflection. What is more, a broad frequency spectrum can be covered in the sound attenuation.
(21) It is not shown that damper 1 may also be designed double-walled to reduce sound emissions even more. A sound-absorbing material can be inserted between two walls of damper 1. With a double-walled structure of damper 1, an air layer between two adjacent walls of damper 1 can also already contribute to a reduction of noise emissions.
(22) It will be understood that a corresponding insulation 28 in principle can also be provided in other areas of damper 1. Moreover, the possibility exists of encapsulating an insulating material toward the interior of damper 1 to prevent soiling of the insulating material by the milling material.
(23) It will further be understood that damper 1 can also have an inner contour that differs from the inner contour shown in FIG. 1 and FIG. 2. For example, the lower, proximal damper portion 20 can also have a cross-section expansion in the distal direction. In the proximal damper portion 20, the shell surface 25 can be truncated cone-shaped. A jump in cross-section can also be provided in the transition area between the proximal damper portion 20 and the distally subsequent to distal damper portion 20, created by a step in the wall of damper 1. The change in cross section in the transition area between proximal portion 20 and distal damper portion 21 is then discrete or non-continuous. It is also possible that damper 1 going from proximal end 16 until the transition area of distal damper portion 21 the head portion 22 overall is formed truncated cone-shaped with preferably constant increase of shell surfaces 25, 26.
(24) Furthermore, damper 1 is preferably also designed as multiple parts so that, for example, head portion 22 of damper 1 can be detached from the shell portions 20, 21. This simplifies cleaning of damper 1. But damper 1 can also be designed as one-piece.
(25) In particular, damper 1 may be made of stainless steel or also of plastic, and can be formed as an injection molded part.
(26) FIG. 3 shows damper 1 from FIG. 1 after insertion into milling material hopper 11 of the comminution device 2. In FIG. 4, the damper 1 shown in FIG. 2 is shown in the operating state of comminution device 2. The geometry of damper 1 in the area of the proximal damper portion 20 and the distally subsequent to distal damper portion 21 is adapted to the inner geometry of housing lid 10 in the area of milling material hopper 11. This allows damper 1 to be inserted positively and/or non-positively into milling material hopper 11. Preferably, damper 1 is fully supported against milling material hopper 11. It is not shown that a sealing means can also be provided between damper 1 and milling material hopper 11 to prevent an air passage and thus reduce sound transmission.
(27) Milling material hopper 11 can also be insulated with a sound-absorbing material for passive abatement of noise emissions.
(28) It is understood that the centrifugal mills shown in FIGS. 3 and 4 have been selected only as examples in order to show the advantageous use of damper 1 in the area of the milling material channel. The use of the damper 1 described above can also be provided in comminution devices with a different design structure.
(29) As also emerges from FIGS. 3 and 4, the comminution device 2 shown in its basic structure has a drive 29 from which the drive shaft 4 extends in the distal direction. Rotor 5 is placed on the drive shaft 4 through a sleeve-shaped extension 30. A labyrinth plate 31 is provided to guide rotor 5, on which rotor 5 runs with associated labyrinth designs. A labyrinth seal is formed between labyrinth plate 31 and the labyrinth designs of rotor 5 to seal the milling chamber defined by rotor 5 against the drive shaft 4.
(30) FIG. 5 shows a cascade arrangement of a plurality of dampers 1, where the damper geometry corresponds to the geometry of the damper 1 shown in FIG. 1. The upper damper 1 shown in FIG. 5 is inserted with its proximal damper portion 20 into the funnel neck 27 of the lower damper 1 shown in FIG. 5. The cascade arrangement of multiple dampers 1 shown leads to a further reduction of noise emissions. In principle, the possibility of the cascade arrangement of multiple dampers 1 is not restricted to the damper geometry shown. Between the proximal damper portion 20 of the upper damper 1 shown in FIG. 5 and the wall section forming the funnel neck 27 of the lower damper 1 shown in FIG. 5, a sealing means and/or an insulation can be additionally provided to prevent an air passage between the dampers 1 in this area and reduce noise emissions even more. Furthermore, the possibility exists to also arrange more than two dampers 1 as a cascade and connected with each other forming a common milling material channel 12.
(31) In FIGS. 6 and 7 are shown two more embodiments of dampers 1, which can be inserted for noise abatement into milling material hopper 11 of a comminution device 2. In FIG. 8 is shown the damper 1 shown in FIG. 7 after insertion into the milling material hopper 11. Consistent with this, the two dampers shown in FIGS. 6 and 7 each have a cylindrical proximal damper portion 20 and a distally subsequent, truncated cone-shaped distal damper portion 21. The damper geometry in the area of the damper portions 20, 21 is adapted to the inner geometry of milling material hopper 11, so that damper portions 20, 21 are supported against the wall portions of housing lid 10 forming the milling material hopper 11. This is presented partially in FIG. 8 for the dampers 1 shown in FIG. 7. Between damper portions 20, 21 and housing lid 10, a sealing means and/or an insulation can also be provided in the area of milling material hopper 11.
(32) Also in agreement, the two dampers 1 shown in FIGS. 6 and 7 each have an upper edge portion 32. This is provided to support damper 1 on housing lid 10 if damper 1 is inserted into milling material hopper 11 (FIG. 8). Edge portion 32 with a radial outer edge 33 preferably engages fully an upper stepped wall portion 34 of housing lid 10, so that in milling operation of the comminution device 2, damper 1 is attached to the housing lid 10. In particular, the attachment of damper 1 to housing lid 10 is designed such that relative movements between damper 1 and housing lid 10 cannot occur during operation of comminution device 2 that could lead to emission of interference noise. It is understood that this aspect is independent of the structural design shown in FIG. 8 of the connection between damper 1 and housing lid 10.
(33) The damper 1 may be formed integrally. At the hopper outlet, the damper 1 shown in FIG. 6 has a conical wall portion 34, which is held by wall portions 35 extended web-shaped in the axial direction to the other, proximal damper portion 20 and forms its backsplash guard. The milling material is added through inlet opening 19 into damper 1 and then past the web-shaped wall sections 35 in the direction of milling chamber 3.
(34) A backsplash guard at damper 1 can also be formed by a separate conical body, which can be arranged through corresponding retaining elements or retaining portions of damper 1 above a hopper inlet or at the hopper outlet of damper 1.
(35) The damper 1 shown in FIG. 7 has an insert 36 that forms a backsplash guard. The insert 36 can be held locking in inlet opening 19 of damper 1. For this purpose, insert 36 has a corresponding edge geometry in the area of its outer edge. In the embodiment shown, an axial annular edge portion 37 engages the area of entry opening 19 and has a locking connection from within with an axial wall portion 38 of outer edge 32 of damper 1.
(36) Above the hopper inlet of damper 1, at its proximal end insert 36 has a conical wall portion 34 as backsplash guard, connected integrally through wall portions 35 extended web-shaped in the axial direction with a funnel-shaped inlet portion 39 of insert 36. The milling material is supplied through insert 36 past the web-shaped wall portions 35 into the area between insert 36 and damper 1, and from there through outlet opening 18 to milling chamber 3.
(37) As seen from FIG. 8, an eccentric supply of the milling material to damper 1 can be provided. The milling material can be supplied through a chute 40, guided by a cover 41. The cover 41 covers the damper 1 inserted into milling material hopper 11, and can lie on the outer edge of damper 1 and/or be connected with damper 1. By rotating chute 40, sound emissions can be directed through chute opening 42 to a side of comminution device 2 turned away from the user. The sound then preferably exits only through the chute opening 42. For this purpose, cover 41 can be rotatably connected with damper 1 and/or damper 1 can be rotatably connected with housing lid 10.
(38) In FIG. 9, a further embodiment of damper 1 is shown through which an eccentric feed of a milling material to an inclined inlet surface 43 of a milling material hopper 11 of a comminution device 2 is possible. The damper 1 has a damper housing 44, into which a hopper part 45 is inserted. The hopper part 45 has a funnel-shaped wall portion 46, which forms a fill hopper for milling material arranged eccentric to the funnel neck of milling material hopper 11 with a distal inlet opening 19 and a proximal outlet opening 18. The outlet opening 18 is arranged above the inclined inlet surface 45 of milling material hopper 11. This in particular enables an eccentric feed of the milling material into milling material hopper 11, whereby the hopper part 45 supplements milling material hopper 11 upward. The eccentric feed of the milling material through damper 1 results in an even greater reduction of noise emissions in the operation of comminution device 2. The hopper part 45 can also be connected rotatably with damper housing 44, and/or a rotatable connection of damper housing 44 with housing lid 10 can be provided. By rotating hopper part 45, the distance a between the axis of symmetry X1 of hopper part 45 and the axis of symmetry X2 of milling material hopper 11 can be changed as needed.
(39) TABLE-US-00001 List of reference numbers: 1 damper 2 comminution device 3 milling chamber 4 drive shaft 5 rotor 6 annular sieve 7 collection container 8 container lid 9 milling material inlet opening 10 housing lid 11 milling material hopper 12 milling material channel 13 housing 14 base plate 15 arrow 16 proximal end 17 distal end 18 outlet opening 19 inlet opening 20 proximal damper portion 21 distal damper portion 22 head portion 23 inner surface 24 arrow 25 shell surface 26 shell surface 27 funnel neck 28 insulation 29 drive 30 extension 31 labyrinth plate 32 edge portion 33 outer edge 34 wall portion 35 wall portion 36 insert 37 edge portion 38 wall portion 39 inlet portion 40 chute 41 cover 42 chute opening 43 inlet surface 44 damper housing 45 hopper part 46 wall portion Y central longitudinal axis X1 axis of symmetry X2 axis of symmetry a spacing
