The invention relates to a method for cleaning a filter apparatus of a rock drilling rig, the filter apparatus comprising several filter units, each one of which being provided with a filter for separating solid matter from the filtering flow to be conducted through the filter unit, and the method comprising removing the solid matter adhered to the filter by providing the filter unit to be cleaned by means of a cleaning apparatus with a pressure pulse, the flow direction of which is reverse in comparison with the flow direction of conventional filtering.
The invention also relates to a filter apparatus comprising: a frame, a first chamber, into which the flow to be filtered is conducted from a suction channel, a second chamber, from where the filtered flow is arranged to be discharged to a discharge channel, several filter units arranged between the first and the second chamber, each one of which comprising a filter, and through which filter units the filter flow is arranged to pass, whereby the filters are arranged to retain the solid matter in the filtering flow, a cleaning apparatus comprising at least one pressure channel enabling to provide at least one filter unit to be cleaned at a time with a pressure pulse, the direction of which is reverse in comparison with the conventional filtering flow, whereby the pressure pulse is arranged to remove the solid matter in the filter, and at least one control unit for controlling the operation of the cleaning apparatus.
The invention further relates to a rock drilling rig comprising: a movable carrier provided with at least one drilling boom, the outermost end thereof comprising a rock drilling unit including at least a feed beam and a rock drilling machine, a dust collection system including at least one suction apparatus, a filter apparatus and at least one suction channel, the dust collection system also being arranged to suck dust from a drilling hole drilled with the rock drilling machine, and the filter apparatus further comprising: a frame, a first chamber, into which the flow to be filtered is conducted from the suction channel, a second chamber, from where the filtered flow is arranged to be discharged to a discharge channel, several filter units arranged between the first chamber and the second chamber, each one of which comprising a filter, and through which filter units the filter flow is arranged to pass, whereby the filters are arranged to retain the solid matter in the filtering flow, a cleaning apparatus comprising at least one pressure channel enabling to provide at least one filter unit to be cleaned with a pressure pulse, the direction of which is reverse in comparison with the conventional filtering flow, whereby the pressure pulse is arranged to remove the solid matter in the filter, and at least one control unit for controlling the operation of the cleaning apparatus.
A large amount of dust is created when holes are drilled into a rock. A rock drilling rig may be provided with a dust collection system that sucks the dust created and moves the dust to a filter apparatus, where air and solid matter are separated. However, rock dust easily clogs the filters in a filter apparatus, thus weakening the efficiency of the filtering. Increasing the number of filters enables to increase the capacity of the filter apparatus, but then the massive size and the high costs become a problem. Cleaning apparatuses have therefore been developed, which create a pressure pulse inside the filter, the direction of which is reverse in comparison with the conventional suction flow of the filter. The pressure pulse removes the solid matter adhered to the filter. Publication GB 812 244 discloses an example of such a cleaning apparatus. However, a problem with the known solutions is that at least some of the dust removed from the filter immediately returns by impact of the suction to the filter, from where it was removed by means of the pressure pulse. The current cleaning apparatuses are therefore unable to efficiently clean the filter units.
It is an object of the present invention to provide a new and improved method for cleaning a filter apparatus of a rock drilling rig, a filter apparatus and a rock drilling rig.
The method of the invention is characterized by preventing the filtering flow through the filter unit to be cleaned by means of mechanical sealing means during cleaning, and keeping the filter unit to be cleaned sealed for a predetermined time after having provided the pressure pulse.
The filter apparatus of the invention is characterized in that the cleaning apparatus comprises mechanical sealing means for preventing the filtering flow through at least one filter unit to be cleaned during cleaning, and the control unit is arranged to keep the filter unit to be cleaned sealed for a predetermined time after having provided the pressure pulse.
The rock drilling rig of the invention is characterized in that the cleaning apparatus comprises mechanical sealing means for preventing the filtering flow through at least one filter unit to be cleaned during cleaning, and the control unit is arranged to keep the filter unit to be cleaned sealed for a predetermined time after having provided the pressure pulse.
It is an essential idea of the invention to separate one or more filter units to be cleaned by means of sealing means from the filtering flow conducted through the filter apparatus during cleaning. After sealing, the filter unit to be cleaned is provided with one or more pressure pulses. The flow direction of the pressure pulse is reverse to the conventional flow direction of the filter unit to be cleaned. Furthermore, the filter unit to be cleaned is kept sealed for a predetermined time after having provided the pressure pulse. Filtering in the filter units, which are not to be cleaned, is continued in a substantially unchanged manner.
An advantage of the invention is that the dust and other solid matter removed from the filter is allowed to undisturbedly fall towards the bottom of the filter apparatus before the suction flow is again passed through the filter unit. Thus the removed dust is not immediately returned to the cleaned filter. The cleaning is therefore more efficient than before. When the cleaning is efficient then the filter apparatus can be dimensioned to be of a smaller size than previously, and in addition the filters endure longer than before.
An essential idea of an embodiment of the invention is that the filter unit to be cleaned is kept sealed for at least one second after having provided the pressure pulse.
An essential idea of an embodiment of the invention is that the sealing means comprise a funnel, which can be arranged substantially gas-tightly against at least one filter unit so that the suction flow through the filter unit in question is prevented.
An essential idea of an embodiment of the invention is that the cleaning apparatus is moved in relation to the filter units and the cleaning apparatus is placed at the location of the filter unit to be cleaned. The cleaning apparatus may comprise an actuator that allows transferring the pressure channel and the sealing means to the location of each filter unit.
An essential idea of an embodiment of the invention is that the filter units are moved in relation to the cleaning apparatus. The filter units may be arranged on an appropriate circumference in the frame of the filter apparatus, and the frame can be revolved in relation to the middle axle of the frame so that each filter unit can in turn be indexed at the location of the cleaning apparatus.
An essential idea of an embodiment of the invention is that each filter unit is provided with a valve that can be closed so that the suction flow through the filter unit can be prevented for the duration of the cleaning. Furthermore, a specific pressure channel is directed to each filter unit in order to provide a pressure pulse.
An essential idea of an embodiment of the invention is that the suction flow through the filter unit to be cleaned is prevented for the duration of the sealing, the length of which is proportional to the magnitude of the suction formed in the suction unit. The sealing time can be arranged to be longer, the greater the suction to be employed is. The length of the sealing time is also proportional to the distance that the removed solid matter is able to move from the filter unit. A great suction effect may suck the removed solid matter back to the filter unit to be cleaned from a longer distance than a small suction effect, and therefore the sealing time should be longer when a great suction effect is used.
An essential idea of an embodiment of the invention is that the filter unit is cleaned during rock drilling. When the filter unit is cleaned at intervals during conventional drilling, no large amounts of solid matter is collected in the filter unit that could, if a large amount of solid matter were removed in one go, clog the dust separator.
The invention is described in more detail in the accompanying drawings, in which
For clarity, some embodiments of the invention are shown in simplified form in the Figures. Similar parts are indicated with the same reference numerals in the Figures.
What can be arranged between adjacent filter units 19 are walls 32, in which case the suction of the filter unit 19b operating normally is unable to affect the filter unit 19a to be cleaned, whereby the solid matter 21 to be removed in the cleaning will fall onto the bottom of the filter apparatus 21 by the force of gravity.
The pressure channel 24 can be moved in transverse direction A of the filter units 19 for instance by means of a cylinder operating by pressure medium. The filter apparatus 21 may be provided with a control unit 33, which can be arranged to control both the actuator 25 and a control device 34 for example a valve for conducting a pressure pulse from a pressure source 35, for instance from a pump to the pressure channel 24. In addition, the control unit 33 may control the actuator 28 to open and close the hatch 27.
The filter apparatus 21 shown in
The control unit 33 can be arranged to control the operation of the cleaning apparatus 23 in such a manner that the filter unit 19a to be cleaned is kept sealed for a predetermined time after having provided the pressure pulse. The control unit 33 may be provided with a timer that allows determining the sealing time. The sealing time after the pressure pulse may range between 1 and 5 seconds. The solid matter removed is able to move sufficiently far from the filter unit 19a during the sealing time.
Furthermore, the filter unit to be cleaned can be kept sealed for the sealing time, the length of which is proportional to the magnitude of the suction formed by the suction apparatus 13. The magnitude of the suction can be measured using an appropriate measuring device 40a, 40b, a sensor or the like, for instance from the discharge channel 22 or alternatively from the suction channel 14. The measuring information can be forwarded to the control unit 33 along an appropriate data transmission connection 41. It is also possible to determine in the control unit 33 the magnitude of the suction, for instance based on the running speed of the suction apparatus 13 or the driving motor M thereof. For this purpose one or more measuring devices 42, sensors or the like can be arranged at the suction apparatus 13. In addition, the magnitude of the suction may be dependent on the load of a main engine 43 of the rock drilling rig 1, such as a diesel engine or an electric motor. Thus the load of the main engine 43 can be determined and the sealing time can be adjusted proportionally thereto. Other methods are also applicable for determining the magnitude of the suction or the suction effect. The sealing time can be arranged in the control unit 33 to be longer, the greater the suction to be used is. The length of the sealing time is also proportional to the distance that the removed solid matter is able to move away from the filter unit 19a. A significant suction effect is able to suck the removed solid matter back to the filter unit 19a to be cleaned from a longer distance than an insignificant suction effect, and the sealing time should therefore be longer when significant suction is used. The control unit 33 may be provided with a pre-set control strategy, or a control strategy may be set on the basis of which the sealing time is determined in respect of the magnitude of the suction. The above components and measures associated with determining the sealing time are not restricted to be used only with the filter apparatus 12 according to
It should be mentioned that the different embodiments and properties of the invention presented in this application can be combined in order to form various combinations. In some cases the solutions shown may be applied as such regardless of the other properties presented.
The drawings and the specification associated therewith are merely intended to illustrate the idea of the invention. The details of the invention may vary within the scope of the claims.
Number | Date | Country | Kind |
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20045405 | Oct 2004 | FI | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/FI05/50374 | 10/26/2005 | WO | 00 | 4/26/2007 |