Jaw crusher

Abstract

A jaw crusher (1) comprising a load bearing support frame, a first movable jaw (2) and a second movable jaw (3) forming between them a variable crushing chamber (8) having an inlet (6) and an outlet (7), and driving means for driving the fist first movable jaw (2) and the second movable jaw (3) for crushing material present in the crushing chamber (8), wherein the first movable jaw (2) is mounted eccentrically at a first rotatable shaft (4) supported on the support frame and the second movable jaw (3) is mounted eccentrically at a second rotatable shaft (5) supported on the support frame, wherein a first toggle plate (10) is coupled to a lower region of the first movable jaw (2) and a second toggle plate (11) is coupled to a lower region of the second movable jaw (3), characterized in that the first toggle plate (10) is arranged in an up-thrust orientation and the second toggle plate (11) is arranged in a down-thrust orientation and that the first rotatable shaft (4) and the second rotatable shaft (5) are driven for counter-rotation.

Description

[0001] Jaw Crusher

[0002] The invention refers to a jaw crusher comprising a load bearing support frame, a first movable aw and a second movable jaw forming between them a variable crushing chamber having an inlet and an outlet, and driving means for driving the fist first movable jaw and the second movable jaw for crushing material present in the crushing chamber, wherein the first movable jaw is mounted eccentrically at a first rotatable shaft supported on the support frame and the second movable jaw is mounted eccentrically at a second rotatable shaft supported on the support frame, wherein a first toggle plate is coupled to a lower region of the first movable jaw and a second toggle plate is coupled to a lower region of the second movable jaw.

[0003] Most jaw-type crushers usually have a fixed jaw and a large heavy movable jaw known as a pitman which is driven by an eccentric shaft which causes the pitman to move along a noncircular path.

[0004] In other embodiments, jaw crushers have become known that comprise two movable jaws.

[0005] Typically, the bottom of the movable jaw(s) is supported by a toggle plate, which serves the purpose of allowing, within limits, the bottom of the movable jaw(s) to move up and down with the motion of the eccentric shaft, i.e. the toggle plate supports the lower part of the movable jaw and helps in the transmission of the oscillating motion from the eccentric shaft to the jaw. Further, by adjusting the position of the toggle plate, the size of the discharge opening may be changed, thereby allowing the size of the crushed output to be varied . Jaw crushers are versatile machines used for crushing a wide range of materials . They are commonly employed in the mining and construction industries . The typical materials processed through j aw crushers include ores , minerals , rocks , gravel , and demolition debris .

[0006] In construction and demolition, aw crushers play a crucial role in handling rubble and concrete debris . They are used to crush these materials into smaller pieces for recycling or disposal . Similarly, in the production of aggregates for construction, j aw crushers are used to break down rocks and gravel into finer particles .

[0007] Jaw crushers can handle a wide range of material hardness , from soft to very hard, making them suitable for a diverse range of applications . However, the speci fic design and capacity of the j aw crusher determine the si ze and type of material it can ef fectively process .

[0008] In recent years , there has been a gradual increase in the recycling of construction demolition waste for reuse in the production of cement or concrete mixes . In an ef fort to reduce the use of virgin materials in the production of cement and concrete , the construction materials industry has developed several solutions that attempt to maximise the substitution of Portland clinker in cement mixes or the substitution of limestone and clay in clinker raw meal mixes .

[0009] Incorporating construction demolition wastes in cement production can signi ficantly reduce CO2 emissions associated with the cement manufacturing process . This is achieved through reduced limestone calcination, as well as the use of an industrial by-product, which would otherwise require disposal or long-term storage.

[0010] Construction demolition wastes are a mixture of different materials that come from the demolition site of an old construction. It is typically composed of concrete demolition wastes, plasterboards, bricks, steel, wood, tiles or glass. The common practice is to sort these materials in recycling centres, so as to separate the materials listed above to reuse them in applications for which their chemical composition is most suitable.

[0011] These demolition wastes are classified under different waste codes of the European Waste Catalogue (EWC) depending on its composition and potential contamination. The EWC is a hierarchical list of waste descriptions established by EU Commission decision 2000 / 532 / EC2. Construction and demolition wastes fall under chapter 17 of the EWC. Concrete demolition wastes fall under sub-chapter 17 01 und comprises the following waste codes:

[0012] • 17 01 01: concrete

[0013] • 17 01 02 : bricks

[0014] • 17 01 03: tiles and ceramics

[0015] • 17 01 06: mixtures of, or separate fractions of concrete, bricks, tiles and ceramics containing hazardous substances

[0016] • 17 01 07: mixtures of concrete, bricks, tiles and ceramics other than those mentioned in 17 01 06

[0017] Other sub-chapters comprise wood, glass and plastic (17 02) , bituminous mixtures, coal tar and tarred products (17 03) , metals ( 17 04 ) , soil ( 17 05 ) , and other fractions ( 17 06 - 17 09 ) .

[0018] For the purpose of the instant invention, concrete demolition waste according to EWC waste code 17 01 , in particular 17 01 01 and / or 17 01 07 , may be used .

[0019] The products obtained from the crushing of concrete demolition waste are mainly crushed aggregates and cement paste . Crushed aggregates can be used in new construction proj ects . These aggregates can be used as a substitute for natural aggregates in concrete production, road construction and landscaping . The cement paste fraction, once processed, can be used as a supplementary cementitious material in new concrete mixes . It can partially replace Portland cement , reducing the environmental impact associated with cement production .

[0020] In order to optimi ze the reuse of crushed aggregates and cement paste , it would be desirable to obtain these fractions in as pure a form as possible . However, current designs of aw crushers are unsuitable for this purpose as they are designed to crush hard rock but not to achieve ef ficient separation of the cement paste from the aggregates to which the cement paste is adhered .

[0021] It is , therefore , an obj ect of the present invention to improve a j aw crusher so that it is suitable for the crushing of construction demolition waste , meaning that in addition to its crushing function the crusher shall be designed to ef fectively separate cement paste from the aggregate fraction of the waste . In order to solve these obj ects the invention provides a aw crusher comprising a load bearing support frame , a first movable aw and a second movable j aw forming between them a variable crushing chamber having an inlet and an outlet , and driving means for driving the fist first movable j aw and the second movable j aw for crushing material present in the crushing chamber, wherein the first movable j aw is mounted eccentrically at a first rotatable shaft supported on the support frame and the second movable j aw is mounted eccentrically at a second rotatable shaft supported on the support frame , wherein a first toggle plate is coupled to a lower region of the first movable j aw and a second toggle plate is coupled to a lower region of the second movable j aw, wherein the first toggle plate is arranged in an up-thrust orientation and the second toggle plate is arranged in a downthrust orientation and the first rotatable shaft and the second rotatable shaft are driven for counter-rotation .

[0022] The inventive design of the j aw crusher facilitates a crushing action that relies more on attrition and abrasion, as opposed to the predominantly compressive force used in traditional crushers . In traditional designs , where rock is compressed between a fixed and a moving j aw plate , the crushing action is primarily compressive . However, in the design according to the invention, the di f ferential movements of the two movable j aws , each driven by their respective counter-rotating shafts , create a dynamic crushing environment . This environment enhances inter-particle crushing or autogenous rock-to-rock crushing, which is particularly ef fective for liberating the cement paste .

[0023] The up-thrust and down-thrust orientations of the toggle plates contribute to a more complex and ef fective movement of the jaws. This movement not only applies compressive force but also generates significant shear and attrition forces within the crushing chamber. These forces are more effective in breaking down the cement paste that adheres to aggregates in construction demolition waste. The result is a more efficient liberation of cement paste from the aggregates, enhancing the quality of the reclaimed materials for recycling purposes.

[0024] In an up-thrust toggle plate orientation, the angle of the toggle plate forces the movable aw upwards as it moves backward, i.e. away from the opposite movable jaw.

[0025] In a down-thrust toggle plate orientation, the angle of the toggle plate pushes the movable jaw downwards as it moves backward .

[0026] The combination of the first movable jaw having an up-thrust toggle plate and the second movable jaw having a down-thrust toggle plate results in a relative motion of the first and second movable jaw, such that, at least during part of the movement cycle, the crushing face of the first jaw and a crushing face of the second jaw have a vertical movement component pointing in opposite directions. In other words, one jaw has a vertical upwards movement component, while the other jaw has a vertical downwards movement component. Herein, the vertical movement component is understood to denote a movement component extending form the inlet to the outlet of the crushing chamber.

[0027] By having, at least during part of the movement cycle, opposite vertical movement components of the jaws, material arranged in the rushing chamber between the jaws will be subj ected to a sheering or abrasive load, thereby favoring separation of cement paste from aggregates .

[0028] According to a preferred embodiment of the invention, the first toggle plate extends at an angle of 20-70 ° , preferably 30- 60 ° , relative to a straight line that extends through a rotation axis of the first rotatable shaft and a rotation axis of the second rotatable shaft .

[0029] Further, the second toggle plate may preferably extend at an angle of 20-70 ° , preferably 30- 60 ° , relative to a straight line that extends through a rotation axis of the first rotatable shaft and a rotation axis of the second rotatable shaft .

[0030] According to another preferred embodiment of the invention, an orientation of the first movable aw and the second movable j aw relative to one another is convergent along their respective lengths such that a separation distance between a crushing face of the first j aw and a crushing face of the second movable j aw decreases in a direction from the inlet of the crushing chamber to the outlet of the crushing chamber . The convergent orientation facilitates a gradual and controlled reduction of material si ze as it moves through the crusher, enhancing the ef ficiency of si ze reduction and minimi zing the likelihood of clogging or blockage within the crushing chamber . This configuration ensures that larger pieces of material are initially engaged and progressively broken down into smaller fragments as they are guided from the wider inlet to the narrower outlet .

[0031] Preferably, a conveyor belt is arranged at an adj ustable distance below the outlet of the crushing chamber . The adjustable positioning allows for the accommodation of varying sizes of crushed material. By adjusting the distance of the conveyor belt, the width of a gap between the lower end of the jaw crusher, i.e. the outlet of the crushing chamber, and the upper face of the conveyor belt can be adapted to the specific requirements of the crushing process. By adjusting said distance, the flow of material through the crushing chamber can be controlled. If an extended residence time of the material within the crushing chamber is desired, the distance between the outlet and the conveyor belt will be reduced. In the opposite case, the distance between the outlet and the conveyor belt will be increased.

[0032] The flow of material through the crushing chamber may also be adjusted by changing the speed of the moving jaws. Selecting a higher speed will result in that material will be retained in the crushing chamber for longer time.

[0033] Another parameter for controlling the flow of material through the crushing chamber is the inclination of the movable jaws, in particular the inclination of the crushing faces.

[0034] Material may preferably be fed to the crusher with any bulk material feeding device. Examples of a bulk material feeding device include a vibrating feeder, a belt conveyor, a reciprocating feeder and an apron feeder.

[0035] A screening device may preferably be arranged after the jaw crusher, in order to separate sand (typically having a particle size range of 0 / 4mm) and coarse fractions (typically having a particle size range of 4 / 8mm and 8 / 16mm) . The coarse fraction typically will contain the crushed aggregates fraction of the construction demolition waste , while the fine fraction will contain sand a cement paste .

[0036] Preferably, the j aw crusher may be operated with an electric or hydraulic drive that rotates the first and second rotatable shafts of the crusher .

[0037] According to another aspect , the present invention refers to the use of a aw crusher as described above for crushing concrete demolition waste by subj ecting the concrete demolition waste to attrition and abrasion in the crushing chamber, thereby separating a cement paste component of the concrete demolition waste from an aggregate component .

[0038] In the following, the invention will be described in more detail with reference to an exemplary embodiment shown in the drawings . Therein, Fig . 1 shows a cross section of a j aw crusher according to the invention .

[0039] The j aw crusher 1 comprises a pair of opposing movable j aws 2 and 3 , each mounted on distinct rotatable shafts 4 and 5 supported within a load-bearing support frame . The first movable j aw 2 is associated with the first rotatable shaft 4 , and the second movable j aw 3 with the second rotatable shaft 5 . The orientation of the two movable j aws 2 and 3 converges downwards , which means that the space between the j aws narrows from the top inlet 6 to the bottom outlet 7 of the crushing chamber 8 .

[0040] Each of the first and second movable j aws 2 and 3 comprises a crushing face 9 , depicted as the inner surfaces facing toward the crushing chamber 8 , where the material to be crushed is located . The first movable j aw 2 on the left is mounted eccentrically on the first rotatable shaft 4 . This eccentric mounting facilitates a circular motion of the upper region of the first movable j aw 2 that provides the crushing action . Similarly, the second movable aw 3 on the right is also mounted eccentrically, following the same principle .

[0041] The first toggle plate 10 is connected to the lower region of the first movable j aw 2 . This first toggle plate 10 is in an up-thrust position, extending upward at an angle of approximately 40-50 ° relative to a straight line imagined through the rotation axis of both rotatable shafts 4 and 5 .

[0042] The up-thrust orientation of the first toggle plate 10 results in that it will push the lower part of the first movable j aw 2 downwards when the first movable j aw 2 is moved towards the second movable j aw 3 .

[0043] The second toggle plate 11 is arranged in a down-thrust orientation connected to the lower region of the second movable j aw 3 . The down-thrust orientation of the second toggle plate 11 results in that it will push the lower part of the second movable j aw 3 upwards when the second movable j aw 3 is moved towards the first movable j aw 2 .

[0044] The second toggle plate 11 is longer than the first toggle plate 10 , resulting in a more elliptical movement of the lower region of the second j aw 3 , said elliptical movement path having a larger movement component in a vertical direction than in a hori zontal direction .

[0045] Further, large circular flywheels 12 are attached to each of the first and second rotatable shafts 4 and 5 , which, when rotated, impart the necessary momentum to the rotatable shafts 4 and 5 and consequently to the movable j aws 2 and 3 . The counter-rotation of the rotatable shafts 4 and 5 , indicated by the curved arrows 13 and 14 , is enhances the function of this crusher . The counter-rotational movement generates interparticle attrition between the rocks , thus cleaning the surface .

[0046] In an up-thrust toggle orientation, the angle of the toggle forces the movable j aw upwards as it moves backwards . In a down-thrust toggle orientation, the movable aw is pushed downwards as it moves backwards . The counter-rotation of the two j aws creates a shearing force on the particles as the upward movement of one j aw works against the downward movement of the other, downwardly pushing j aw . In addition, the upward movement of the j aw causes the particles to move upward and preventing them from falling down to the outlet , increasing their residence time in the crushing chamber and subj ecting them to extended shearing force .

[0047] At the lower end region of the movable j aws 2 and 3 , the latter form an outlet 7 from where the crushed material exits the crushing chamber 8 to fall onto a conveyor belt 15 for conveying the crushed material to further processing stations , such as a screening device . The vertical distance 16 between the outlet 7 and the conveyor belt 15 can be adj usted to control the outflow volume per time unit of the crushed material .

Claims

Claims :

1. A j aw crusher comprising a load bearing support frame, a first movable jaw (2) and a second movable aw (3) forming between them a variable crushing chamber (8) having an inlet (6) and an outlet (7) , and driving means for driving the fist first movable jaw (2) and the second movable jaw (3) for crushing material present in the crushing chamber (8) , wherein the first movable jaw (2) is mounted eccentrically at a first rotatable shaft (4) supported on the support frame and the second movable jaw (3) is mounted eccentrically at a second rotatable shaft (5) supported on the support frame, wherein a first toggle plate (10) is coupled to a lower region of the first movable jaw (2) and a second toggle plate (11) is coupled to a lower region of the second movable jaw (3) , characterized in that the first toggle plate (10) is arranged in an up-thrust orientation and the second toggle plate (11) is arranged in a down-thrust orientation and that the first rotatable shaft (4) and the second rotatable shaft (5) are driven for counter-rotation.

2. Jaw crusher according to claim 1, wherein the first toggle plate (10) extends at an angle of 20-70°, preferably 30-60°, relative to a straight line that extends through a rotation axis of the first rotatable shaft (4) and a rotation axis of the second rotatable shaft (5) .

3. Jaw crusher according to claim 1 or 2, wherein the second toggle plate (11) extends at an angle of 20-70°, preferably 30-60°, relative to a straight line that extends through a rotation axis of the first rotatable shaft (4) and a rotation axis of the second rotatable shaft (5) .

4. Jaw crusher according to claim 1, 2 or 3, wherein an orientation of first movable jaw (2) and the second movable aw (3) relative to one another is convergent along their respective lengths such that a separation distance between a crushing face (9) of the first movable jaw (2) and a crushing face (9) of the second movable jaw (3) decreases in a direction from the inlet (6) of the crushing chamber (8) to the outlet (7) of the crushing chamber (8) .

5. Jaw crusher according to anyone of claims 1 to 4, wherein a conveyor belt (15) is arranged at an adjustable distance below the outlet (7) of the crushing chamber (8) .

6. Jaw crusher according to anyone of claims 1 to 5, wherein the second toggle plate (11) has a length that is at least 50% larger than the length of the first toggle plate (10) .

7. Use of a jaw crusher according to any one of claims 1 to 6 for crushing concrete demolition waste by subjecting the concrete demolition waste to attrition and abrasion in the crushing chamber, thereby separating a cement paste component of the concrete demolition waste from an aggregate component.

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