Gyratory Crushers

Abstract

The invention concerns gyratory crushers and proposes that the bowl in such a crusher be adjustably supported by hydraulic piston/cylinder units, hydraulically actuated wedges positioning the bowl radially when in use, and that the bowl be held in an adjusted position by locking hydraulic liquid on one side of the pistons of the support units whilst permitting the release of the bowl from the adjusted position in the event of the intrusion of tramp iron or the like. The crusher comprises a control system having elements for locking liquid on said sides, sensing elements for sensing the pressure on said sides and for actuating the locking elements to release said liquid in the event that tramp iron or the like intrudes into the crushing chamber and hydraulic acumulator elements connected to the other sides of the pistons such that, when the locked liquid is released, the bowl is automatically raised to clear the tramp iron by liquid pressure derived from said accumulator means.

Description

This invention relates to gyratory crushers; that is to say it relates to crushers having a fixed base frame, a concave bowl supported on said base frame, and a head which gyrates within said base frame and said bowl the head being spaced from the bowl to define an annular gap or crushing chamber through which rock or other material to be treated is passed and crushed between the bowl and the head as the latter gyrates.

In particular, the present invention concerns a gyratory crusher of the kind (hereinafter referred to as "of the kind set forth") as shown for example in U.S. Pat. No. 3,604,640, in which the bowl is supported relatively to the head by a plurality of hydraulic piston/cylinder support units connected between the base frame and the bowl.

The present invention sets out to provide a gyratory crusher of the kind set forth which can deal with the intrusion of uncrushable material, such as tramp iron, into the crushing chamber in an automatic fashion.

According to the present invention in a gyratory crusher of the kind set forth the piston/cylinder support units are of the double-acting type and the bowl is supported in an adjusted position by locking liquid on one side of the piston of each of the support units so as to provide a liquid abutment against which the piston acts to transmit axial components of the crushing load to the base frame; each of the said piston/cylinder support units is controlled by a system which incorporates a release valve for releasing liquid trapped on the said side, sensing means for sensing the liquid pressure in said side and for opening the relief valve means to release the trapped liquid in the event that the liquid pressure exceeds a predetermined level, and hydraulic accumulator which is connected, when the crusher is in use, to the other side of each of the support units so as to bias the bowl towards a position in which the crushing chamber is opened to the maximum extent, the arrangement being such that, in the event of the intrusion of uncrushable material, the liquid which is trapped in the support units is reduced and thereupon the bowl is moved to open the crushing chamber thereby to clear the uncrushable material by the action of liquid pressure derived from the hydraulic accumulator.

Thus, whenever tramp iron or the like intrudes into the crushing chamber, the bowl is automatically released from the position to which it has been adjusted and is driven by the pressure derived from the accumulator to release and clear the obstruction. This contrasts with the arrangement incorporating disc springs or the like since, in the latter arrangement, the force which is required to lift the bowl can only be generated by the action of the tramp iron against the bowl.

Preferably the relief valve is controlled by a timer which is arranged to automatically close the relief valve a predetermined length of time after it has been opened by the sensing means thereby to enable the bowl to be returned to the adjusted position; the said length of time being selected to ensure that the chamber is opened to a sufficient extent to permit the passage of any size of uncrushable material likely to be encountered.

Preferably the control system is arranged to automatically return the bowl to its adjusted position once the latter has been cleared of tramp iron. To this end the system may also include position sensing means, e.g., limit switches, for sensing the arrival of the bowl at the adjusted position and pump means for supplying liquid to the sides of the piston/cylinder support units in which liquid is normally locked when the crusher is in use, which pump means is energized whenever the bowl moves out of the adjusted position. Thus when tramp iron is encountered, the pump means is activated whilst the bowl is moving upwards but does not become effective to return the bowl towards the adjusted position until the timer closes the release valve.

In the preferred embodiment of the invention the abovementioned pump means is utilised to alter the size of crushing chamber when adjustment of the latter is desired. The system is provided with a directional valve connected to direct the output from the pump means to either side of the pistons of piston/cylinder support units; this directional valve may be automatically actuated by the position sensing means so that the bowl may be re-set to a new adjustment merely by appropriate alteration of the position sensing means.

The invention will now be described with particular reference to a gyratory crusher of the kind set forth as described in said U.S. Pat. No. 3,604,640 and to the accompanying drawings in which:

FIG. 1 corresponds with FIG. 1 of the drawings which accompanied said U.S. Pat. No. 3,604,640,

FIG. 2 shows, in diagrammatic form, the important features of FIG. 1, and one exemplary form of control system for the crusher, and

FIG. 3 shows, again in diagrammatic form, certain modifications of the system of FIG. 2.

FIG. 1 is a partial vertical cross-section through a gyratory crusher of the kind set forth. The cylindrical bottom frame of the crusher is designated 1, this constituting a housing, in the usual way, for the gyratory head which has been generally designated 2. The form of this head is not material to the invention, but in the case illustrated is shown as having a central fixed shaft 25, an eccentric cap 26 which is rotatable on shaft 25, from a power unit (not shown) through a bevel gear 27, and a cone 28 which is given a consequent eccentric motion.

The concave bowl of the machine is designated 3, and it will be observed that this is mounted on an upper frame structure 4, by virtue of a bevelled angular shoulder 5 of the latter receiving a corresponding outer bevelled face of the bowl 3.

The upper frame structure 4, and with it the bowl 3, are supported and adjusted when required by a set of piston/cylinder support units disposed at regular intervals around the base frame 1. One of these units is illustrated at 6 and it will be observed that the cylinder thereof is pivotally mounted at 7 on a peripheral flange 8 extending outwards from the frame 1. The piston rod or ram 9 of the unit is pivotally coupled at 10 to a bracket on the structure 4. The latter can therefore be raised and lowered by appropriate routing of hydraulic fluid into the lower or upper sides of the support units 6 respectively, thereby to increase or decrease the size of the gap 11 between the confronting faces of the head 2 and the bowl 3, i.e., of the crushing chamber.

It is further to be noted that the base frame 1 is provided at its upper end with an annular bevel surface 12. This, in conjunction with the opposed cylindrical wall portion 13 of the structure 4 forms a tapered bight to receive a set of bowl-centralizing wedges, again spaced around the periphery of the base frame 1. One of these wedges is shown at 14 and it will be observed that it is pivotally connected at its lower end 15 to a piston/cylinder unit 16 hinged at 17 to the lower exterior of frame 1.

As will be evident from the drawings, when the wedges 14 are withdrawn the bowl 3 will be supported only by the hydraulic liquid in cylinders 6, but with the wedges 14 pushed into position the load of the bowl is, partly at least, taken by the base frame 1. The bowl is both supported and restrained axially to resist crushing loads and the assembly of wedges 14, which, in effect forms a split wedge ring, restrains the crushing forces radially and to some extent axially.

Although the wedges 14 play only a small part in supporting the bowl 3 and adjustment could be effected by simply pressurising the cylinders 6 to lift or lower the bowl 3 as required, it may be more convenient to release these wedges before adjusting the bowl. Thus in order to carry out an adjustment of the size of crushing chamber 11, and starting with the mechanism in the working position illustrated in FIG. 1, the wedges 14 are first released by pressurising the upper chamber of hydraulic cylinders 16. The bowl 3 is then supported solely by the cylinders 6.

The cylinders 6 are next pressurised at one side or the other to raise or lower the bowl whereafter, with the latter at the required setting, fluid is again locked in cylinders 6. The cylinders 16 are then pressurised to raise and lock the wedges 4 thereby ensuring that the bowl is in a centralised position with respect to the base frame 1 and therefore to the axis of rotation of the head 2 and is supported against radial movement under the influence of radial components of any crushing forces to which it is subsequently subjected.

FIG. 2 shows the bowl 3 and, at 6, three of a set of six double acting piston/cylinder support units which adjustably support the bowl 3 above the base frame 1. It will be appreciated that the support units 6 are disposed around the bowl in vertical dispositions and have been shown separately from the latter merely for ease of illustration.

Each of the piston cylinder support units 6 is divided into two chambers 6a and 6b by its piston 9. Movement of the piston 9 upwards as shown in the drawings raises the bowl 3 to increase the size of the crushing chamber while movement of the piston 9 downwards closes the crushing chamber.

In the crusher shown in FIG. 1 the wedges 14 play only a small part in supporting the bowl 3 and serve principally to prevent radial movement of the latter when the crusher is in operation. The bowl is therefore supported by trapping hydraulic liquid on the upper side of the pistons 9 i.e., in the chambers 6a so that the trapped liquid forms a liquid abutment against which the axial components of the crushing load are directed; since hydraulic liquid is to all intents and purposes incompressible the bowl is held rigidly whilst liquid remains trapped in the chambers 6a.

Adjustment of the size of crushing chamber is effected by raising or lowering the pistons 9 and hence the bowl 3 by any desired amount. This is achieved by admitting hydraulic fluid either to the chambers 6a or to the chambers 6b as required.

Thus the support units 6 serve not only to hold the bowl in any adjusted position when in operation, but also to raise and lower the bowl when the size of crushing chamber is to be adjusted. The control systems shown in FIGS. 2 and 3 therefore have two distinct functions. Firstly they serve to control the piston/cylinder support unit 6 whilst the crusher is in operation; the parts of the system which perform this function are enclosed within the chain dotted boxes A and A' in FIG. 2. Secondly they control the movement of the pistons 6c of the support units when the bowl is to be moved to a preselected position; the parts of the system which perform this function are enclosed within the chain dotted box B in FIG. 2. An electrical control panel C provides manual switches for controlling the crusher and energises the various electrical components of the system when necessary.

Referring first to the parts of the system within the boxes A and A', it can be seen that the upper chambers 6a are interconnected by means of a pipe-line 31 to a pressure switch 32 and also to a solenoid operated pilot check valve 33 which has an actuating solenoid 34 and constitutes the release valve of the invention.

The lower chambers 6b of the support units 6 are interconnected by a pipe-line 35 and a connector block 36 to an hydraulic accumulator 37. This latter component is not shown in detail but comprises a cylinder within which there is a partition consisting of an impermeable membrane. This partition divides the interior of the cylinder into two parts one of which is charged with gas under an appropriate pressure and the other of which is connected to the chambers 6b. The pressurised gas acts, in effect, as a spring which tends to force hydraulic liquid from the accumulator into the chambers 6b thereby to raise the bowl 3. This tendency is, of course, resisted under normal operating conditions by the liquid locked in the chambers 6a so that the pressure in the latter depends largely on the axial component of the crushing forces and partly on the pressure charge in the accumulator 37, this latter pressure remaining constant under normal operating conditions.

The pressure switch 32 senses the pressure in the upper chambers 6a and is preset to operate at a predetermined pressure so as to energise the solenoid 34 via a timer 38 thereby to open the check valve 33 and relieve the pressure in upper chambers 6a. Thus when the crusher is in normal operation and uncrushable material such as tramp iron enters the crushing chamber the pressure in the upper chambers 6a increases until it exceeds the predetermined value set by the pressure switch 32. When this value is exceeded the pressure switch 32 energises the solenoid 34 to open the check valve 33 and vent the upper chambers 6a. Since the lower chambers 6b are under constant pressure from the hydraulic accumulator 37 the bowl 3 will instantly be lifted, opening the crushing chamber and allowing the obstruction to pass therethrough. The timer 38 maintains the check valve 33 in an open condition for a predetermined length of time so as to ensure that the bowl 3 is raised by a sufficient amount to clear the obstruction. The timer 38 then closes the valve 33 so that the bowl can be reset to the adjusted position.

Resetting of the bowl 3 is achieved by re-pressurising the upper chambers 6a. To this end the portion of the system in the box B includes a hydraulic pump 29 to which is connected a drive motor 30. The pump 39 is arranged to draw hydraulic liquid from a reservoir 39 and discharge it by way of a directional solenoid-operated valve 40 into the pipeline 31 and thence to the upper chambers 6a. A linear potentiometer 41 is connected between the upper frame and the base frame of the crusher and controls a position-indicating meter 42 which is associated with the control switch gear of the pump motor 30.

The meter 42 is provided with a manually settable pointer 42a in addition to its indicating pointer 42b. This latter pointer, which is moved in response to changes in electrical resistance in the potentiometer 41 and hence to movement of the bowl 3, is arranged to cause de-energisation of the pump motor 30 when it overlies the pointer 42a. Therefore when the bowl 1 is moved to release tramp iron or the like the pump motor 30 is automatically energised and supplies liquid via the valve 40 into the upper chambers 6a. As a result re-pressurisation of the upper chambers 6a commences as soon as the timer 38 closes the check valve 33 and the bowl is automatically returned to its adjusted position in which the pointers 42a and 42b coincide. When this condition is reached the motor 30 is de-energised.

If, for any reason, the bowl is to be adjusted upwardly the directional valve 40 is energised to direct the output of the pump 29 into the lower chambers 6b, the hydraulic accumulator being isolated to retain its charge. Thus the pistons 9 of the support units 6 are moved upwardly, liquid being displaced from the chambers 6a through the pilot check valve 33 to the reservoir 39. The directional valve 40 is controlled by the potentiometer 41 so as to direct liquid to the appropriate side of each of the support units. The potentiometer 41 may incorporate a pair of simple on-off switches arranged on each side of any adjusted position and connected to energise the appropriate winding of the directional valve 40 when the bowl is to be adjusted. Alternatively means may be arranged to sense the desired direction of movement of the bowl.

FIG. 3 shows a simplified arrangement in which the linear potentiometer 41 has been replaced by a simple limit switch 41a controlled by a probe 41b on the upper frame. In this arrangement the meter 42 is dispensed with and the limit switch is arranged to control the motor 30 directly. In the normal operating position the probe 41b will be in engagement with the limit switch 41a mounted on the main frame. When the concave bowl lifts due to an overload the probe will also rise releasing its contact against the limit switch. The hydraulic pump will supply fluid to lower the bowl assembly until the probe again contacts the limit switch when the motor starter will be de-energised.

Arrangements may be made for automatically withdrawing the centralising wedges shown therein whenever the bowl is to be adjusted; these wedges will, however, remain engaged while the piston/cylinder units are operated to relieve tramp iron and the like.

Claims

I claim:

1. A gyratory crusher comprising in combination a fixed base frame, a concave bowl supported adjustably on said base frame, a head which gyrates within said base frame and said bowl to define an annular gap or crushing chamber through which material to be treated is passed and crushed between the bowl and the head as the latter gyrates; adjustable support means for said concave bowl said support means comprising a plurality of hydraulic piston/cylinder support units connected between the base frame and wedge units engaged between said base frame and said bowl to locate the latter radially with respect to the axis of rotation of the head; means for locking hydraulic liquid on one side of the piston of each of said support units to provide a liquid abutment against which the piston acts to transmit axial components of the crushing load to the base frame and releasing said liquid at required times; sensing means sensing the liquid pressure of said locked liquid and releasing said locking and releasing means when the pressure exceeds a predetermined level, and hydraulic accumulator means connected to the other side of each of said support units to bias the bowl towards a position in which the crushing chamber is opened to the maximum extent, so that, in the event of the instrusion of uncrushable material, the liquid locked in the support units is released and thereupon the bowl is moved to open the crushing chamber, thereby to clear the uncrushable material, by the action of liquid pressure derived from the hydraulic accumulator means.

2. A gyratory crusher in accordance with claim 1 further comprising a timer which controls the said locking and releasing means to return the latter to the locked condition a predetermined length of time after it has been actuated by the sensing means so that the bowl may be returned to the adjusted position, said length of time being selected to ensure that the chamber is opened to a sufficient extent to permit the passage of any size of uncrushable material likely to be encountered.

3. A gyratory crusher in accordance with claim 2, further comprising position sensing means arranged to sense the arrival of the bowl at the adjusted position, and pump means for supplying liquid to the sides of the said support units in which liquid is normally locked when the crusher is in use, the pump means being activated whenever the bowl moves out of the adjusted position as a result of actuation of said locking and release means by the sensing means but remaining ineffective until the latter is returned to the locked position by the timer.

4. A gyratory crusher in accordance with claim 3, further comprising a directional valve connected to direct the output from the pump means to either side of the pistons of the said support units thereby to permit the crushing chamber to be set to a plurality of selected sizes.

5. A gyratory crusher in accordance with claim 4, further comprising sensing means arranged to control the directional valve so that adjustment of the sensing means to select a new size of crushing chamber automatically actuates the directional valve to cause movement of the bowl to an appropriate position.