Monitoring System

Abstract

The present disclosure relates to a monitoring system for a hydraulic system in a comminution apparatus including at least one pressurized accumulator. The monitoring system includes at least one pressure sensor and a control unit, wherein the pressure sensor is connected to the control unit. The pressure sensor is arranged to measure a pressure in the at least one accumulator and the control unit is configured to determine that a pressure in the accumulator is outside of a predefined range. The control unit is further configured to control a pressure regulating system that is arranged to restore the pressure in the pressurized accumulator.

Claims

1.-15. (canceled)

16. A monitoring system for a hydraulic system in a comminution apparatus including at least one pressurized accumulator, wherein the pressurized accumulator comprises a first chamber containing hydraulic liquid and a second chamber containing a pressurized gas, wherein said monitoring system comprises at least one pressure sensor and a control unit, wherein said pressure sensor is connected to said control unit, said pressure sensor being arranged to measure a pressure in said at least one accumulator and wherein the control unit is configured to determine that a pressure in said accumulator is outside of a predefined range and wherein the control unit is further configured to control a pressure regulating system arranged to restore the pressure in the pressurized accumulator, wherein the pressure sensor is arranged to measure a gas pressure in said second chamber.

17. The monitoring system in accordance with claim 16, wherein the second chamber of each accumulator is connected to a source of pressurized gas.

18. The monitoring system in accordance with claim 16, wherein the control unit is configured to continuously monitor the pressure in the accumulator.

19. The monitoring system in accordance with claim 16, wherein the control unit is configured to determine that a pressure in said second chamber is outside of a predefined range.

20. The monitoring system in accordance with claim 16, wherein the gas comprises nitrogen.

21. The monitoring system in accordance with claim 18, wherein the control unit is configured to control a pressure regulating system arranged to restore a pressure in said second chamber.

22. The monitoring system in accordance with claim 16, wherein the second chamber of each accumulator is connected to a source of pressurized gas via a manifold block.

23. The monitoring system in accordance with claim 22, wherein the manifold block comprises solenoid valves.

24. The monitoring system in accordance with claim 16, wherein the control unit is configured to determine the pressure in the at least one accumulator at pre-defined time intervals.

25. The monitoring system in accordance with claim 16, wherein the control unit is configured to continuously determine the pressure in the at least one accumulator.

26. The monitoring system in accordance with claim 16, wherein said control unit is configured to determine the occurrence of a tramp event based on information from said pressure sensor.

27. A comminution apparatus including at least one pressurized accumulator comprising a first chamber containing hydraulic liquid and a second chamber containing a pressurized gas, said comminution apparatus comprising a monitoring system, wherein said monitoring system comprises at least one pressure sensor and a control unit, wherein said pressure sensor is connected to said control unit, said pressure sensor being arranged to measure a pressure in said at least one accumulator and wherein the control unit is configured to determine that a pressure in said accumulator is outside of a predefined range and wherein the control unit is further configured to control a pressure regulating system arranged to restore the pressure in the pressurized accumulator, wherein the pressure sensor is arranged to measure a gas pressure in said second chamber.

28. A method of monitoring a hydraulic system in a comminution apparatus having a monitoring system in accordance with claim 16, said method comprising the steps of: arranging a pressure sensor at an accumulator of a hydraulic system of said comminution apparatus; transmitting output from said pressure sensor to a control unit; and using said control unit to control a pressure regulating system arranged to restore the pressure.

29. The method in accordance with claim 28, further comprising the step of: based on said output, determining the occurrence of a tramp event.

30. The use of the monitoring system as claimed in claim 16 in a comminution apparatus.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The invention will be described in more detail and with reference to the appended drawings in which:

[0029] FIG. 1 shows a schematic structure of the disclosed invention.

DESCRIPTION OF EMBODIMENTS

[0030] The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplifying embodiments of the invention are shown. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness, and to fully convey the scope of the invention to the skilled addressee. Like reference characters refer to like elements throughout.

[0031] FIG. 1 shows a schematic structure of how the present invention can be organized. Three accumulators 100 are indicated in the drawing. The number of accumulators is of little relevance since different comminution equipment will require different numbers of accumulators 100. These accumulators are provided as a part of a hydraulic system 104 of the comminution equipment. Each of the accumulators comprises a first chamber 102 containing hydraulic oil and a second chamber 101 comprising pressurized gas, for example nitrogen. The two chambers are separated by means of for example a bladder, a piston or a diaphragm, or combinations thereof. The accumulators are provided to compensate and absorb sudden and often excessive load bursts. Such load bursts may for example occur during a so called tramp event, i.e. when an uncrushable object, for example a piece of metal, enters a crushing equipment. When such object enters e.g. a cone crusher, the hydraulic system has to handle a sudden and large load burst. This load burst is absorbed by the pressurized gas in the second chamber 101 which will act much like a shock absorber. The oil in the hydraulic system 104 will be forced towards the second chamber thus reducing the volume available to the gas and therefore increasing the pressure in the second chamber 101. At the end of the tramp event, the pressure in second chamber 101 will force the hydraulic oil back and out of the accumulator until a pressure balance is achieved. It is clear that there is a range of pressure within which this system will work as deigned and that high risks are involved in neglecting the monitoring of the pressure in the hydraulic system since a too low pressure may cause catastrophic failure of major components of e.g. a cone crusher. The present invention therefore suggests that pressure sensors 103 are mounted to each of the accumulators 100, for example at each of the second chambers 101, and that these sensors 103 are connected to a control unit 300. This control unit 300 is further connected to a valve arrangement 400 and possibly also to a source of pressurized gas 500. The pressure sensors 103 provide output to the control unit 300. This can be done continuously or intermittent, possibly only on request by the control unit 300. The control unit 300 is further connected to a valve arrangement 400 which is arranged to connect each of the second chambers 101 to a source of pressurized gas 500. The control unit 300 evaluates the output from the pressure sensors 103 and determines whether or not the pressure in each of the accumulators lie within a pre-defined range. Should the pressure in one or more of the second chambers 101 lie outside of the pre-defined range, within which it has been determined that the equipment will function as designed and fulfil the requirements placed thereon, the control unit 300 may automatically activate one or more valves in the valve arrangement 400 such that the pressure in the second chamber(s) in question can be restored. The valve arrangement 400 may in one embodiment comprise a manifold or manifold block comprising all required valves and connections. The valves used in such manifold or manifold block may comprise solenoid valves. Solenoid valves have the advantage that they can use weak signals to control high or very high pressures. In one embodiment, the second chambers 101 of the accumulators 100, the valve arrangement 400 and the gas source 500 may be connected by permanent piping, thus reducing or entirely avoiding work related to coupling the parts together when re-charging of the second chambers 101 is required. The control unit 300 may in one embodiment have a semi-automatic function and alert staff members, by means of messages, flashing lights, sound or any other suitable means, that re-charging of one or more second chambers 101 is required. The staff will then take the next step and make sure that this done.

[0032] Further, there may be ball valves 105, or other suitable valve types, arranged in connection to each of the second chambers. These valves 105 can be used to isolate individual accumulators for e.g. maintenance or in order to bleed down or other purposes. These valves 105 may be arranged up- or downstream of the valve arrangement 400, depending on how the valve arrangement 400 is structured. In any case, the valves 105 should only affect the second chamber 101 of a designated accumulator and not that of any other accumulator. Further, by opening all valves 105 and connecting them to a solenoid valve, an automatic system can be created. A control valve 106 may also be arranged to determine leakage before valve arrangement 400. If there is a break in the line, which sometimes may be very long, an alarm can be set of. A valve 107 may be provided which will close upon pressure loss. Other solutions are conceivable and may be applied with similar results.

[0033] The control unit 300 may also be connected to the gas source directly to control the supply of pressurized gas to the valve arrangement 400. This can be done to add a further step of security. In another embodiment, the gas source is always open towards the valve arrangement 400 and as soon as the valve(s) to one or more second chamber(s) is/are opened, re-charging will take place.

[0034] In another embodiment of the present invention, the pressure sensors in the second chambers 101 can be used to detect tramp events. Current solutions for detecting tramp events normally use vibration sensors comprising accelerometers arranged on the equipment. These accelerometers measure the level of vibrations and tramp events are detected in the output of these. However, they are susceptible to all kinds of vibrations, even vibrations originating in adjacent comminution equipment, making it hard to determine tramp events with a high degree of certainty. Thus, present solutions are only semi-reliable. The present invention instead uses the pressure sensors 103 in the second chambers 101. Live and continuous monitoring of the gas pressure in the second chambers 101 will replace the use of accelerometers to monitor system tramping. A corresponding spike in gas pressure within the accumulators will occur as a tramp event occurs. As it turns out, this reading will be insulated from any background noise from other sources within the plant, meaning it will be a much more accurate measure of the occurrence and severity of a tramp event. Ongoing efforts to collect data and monitor the crusher's operation will be greatly benefitted by improvement of the accuracy of available data.

[0035] The skilled person realizes that a number of modifications of the embodiments described herein are possible without departing from the scope of the invention, which is defined in the appended claims. For example, cone crushers are used as example herein. However, the type of equipment on which the invention is applied is of less relevance. The situation is the same or at least very similar in many types of equipment, for example jaw crushers, gyratory crushers, high pressure roller crushers, high pressure grinding roll, and the advantages stated herein apply correspondingly.