Apparatus and method for heating hydraulic impact equipment

Abstract

To provide equipment and a method for heating an impact apparatus of a rock processing machine under low-temperature operating conditions.SOLUTION: Equipment comprises a warm-up mode WM for supplying pre-heated hydraulic fluid through a supply channel 19 to a hydraulic circuit 18 of an impact apparatus. The hydraulic circuit includes one or more hydraulic accumulators. The supply channel is provided with a control element CE for limiting the supply of the pre-heated hydraulic fluid during the warm-up mode. The control element limits the supply of the pre-heated hydraulic fluid in the supply channel such that a separation element of the pressure accumulator is not displaced.SELECTED DRAWING: Figure 3

Description

[Background technology]

[0001] The present invention relates to an arrangement for heating hydraulic impact equipment of a rock processing machine at low temperature operating conditions.

[0002] The invention further relates to a method for heating hydraulic impact equipment of a rock drilling machine and a rock processing machine.

[0003] The field of the invention is more particularly defined in the preambles of the independent claims.

[0004] In mines and other work sites, different types of rock drilling rigs equipped with rock drilling machines are used to drill boreholes into rock surfaces. Other work machines, such as excavators equipped with hydraulic rock breakers, are also used to break up rock. Rock drilling machines and rock breakers typically include hydraulic impact equipment connected to the hydraulic system of the base machine. These machines often need to be able to operate in low-temperature operating conditions, at least during the winter. Cold temperatures affect the viscosity of the hydraulic fluid in the hydraulic system, as well as elastomeric materials such as seals and pressure separators in pressure accumulators. Therefore, different types of equipment are designed to preheat the hydraulic fluid and the system before starting normal operation. However, known solutions present several drawbacks. Summary of the Invention

[0005] It is an object of the present invention to provide a new and improved installation for heating percussion equipment, a rock drilling rig equipped with such a heating installation, and a method for heating percussion equipment.

[0006] The installation according to the invention is characterized by the characterizing features of the first independent device claim.

[0007] The rock drilling rig according to the invention is characterized by the characterizing features of the second independent equipment claim.

[0008] The method according to the invention is characterized by the characterizing features of the independent method claim.

[0009] The disclosed solution concept is that hydraulic impact equipment of a rock processing machine is preheated in a heating facility for use in low temperature operating conditions. The facility has a selectively executable warm-up mode for supplying preheated hydraulic fluid through at least one supply channel to a hydraulic circuit of the impact equipment. The hydraulic circuit is connected to one or more pressure accumulators to which a pre-charge pressure is applied. The supply channel has at least one control element for limiting the supply of preheated hydraulic fluid in response to the warm-up mode being selected. The control element limits the supply of preheated hydraulic fluid in the supply channel so that its pressure falls below a first pre-charge pressure of a first pressure accumulator located first downstream in the supplied flow.

[0010] In other words, limited, gentle hydraulic power is provided to the impact device to perform the warm-up. This solution aims to prevent compression and volume changes in the gas space of the pre-charged pressure accumulator during warm-up. The gas space is filled with gas, and a membrane, piston, or other separating element separates the gas space from the fluid space of the pressure accumulator. Since the hydraulic fluid is supplied at a pressure lower than the pre-charge pressure during warm-up, movement of the separating element can be avoided. This goal is based on the fact that the pre-heated hydraulic fluid supplied to the hydraulic circuit of the impact device during warm-up cannot compress the gas inside the gas space.

[0011] The advantage of this solution is that it is possible to avoid the movement of the pressure accumulator membrane during warm-up, thereby not directing harmful stresses on the membrane at low temperatures. In this way, it is possible to avoid membrane breakage and increase the membrane's operational life. This reduces the maintenance costs and downtime of the rock drilling machine. A further advantage is that this solution may allow the use of membrane materials whose durability is reduced or insufficient at low temperatures, such as nitrile rubber (NBR). It is generally known that the brittleness of elastomeric materials increases at low temperatures.

[0012] In piston-type accumulators, the disclosed solution may prevent damage to the piston seals.

[0013] Because reduced hydraulic power is implemented during warm-up, the warm-up mode performed is also gentle on other components, such as seals, that are part of or connected to the hydraulic circuit of the impact equipment.

[0014] A further advantage is that the stress and wear experienced by the seals of the impact equipment can be reduced when the hydraulic power supplied during the warm-up mode is limited. The impact equipment operates at a lower frequency during the warm-up mode, so that the sliding speed of the seals remains low. Also, the pressure acting on the seals is low and constant, which has a positive impact on their durability.

[0015] According to one embodiment, the at least one control element is configured to limit the flow and / or pressure of the preheated hydraulic fluid being supplied during the warm-up mode, i.e., the hydraulic power being supplied during warm-up is controlled such that the hydraulic pressure remains below its pre-charge pressure in the first pressure accumulator.

[0016] According to one embodiment, the rock processing machine is a rock drilling machine for drilling a borehole in a rock surface. The rock drilling machine comprises a hydraulic impact device for directing an impact pulse at a drilling tool. Typically, there is also a rotation device for rotating the drilling tool.

[0017] According to one embodiment, the disclosed solution can also be implemented in hydraulic rock breaking machines intended to break rocks in mining and construction work sites, which are equipped with impact equipment and also have hydraulic accumulators that need to be protected when starting the striking operation at low ambient temperatures. Thus, in this embodiment, the rock processing machine is a hydraulic rock breaking machine, also known as a hydraulic breaker and hydraulic breaking hammer.

[0018] According to one embodiment, the control element is configured to limit the flow of hydraulic fluid supplied so that the frequency of the impact device is less than 10% of the frequency in normal operating mode at warm-up. For example, the frequency of the impact mechanism can be limited to 1 Hz for an impact device whose normal operating frequency is 30 Hz.

[0019] According to one embodiment, the installation includes at least one pressure sensor for sensing the pressure prevailing in the gas space of the at least one pressure accumulator. In this way, it may be possible to control the supply of hydraulic fluid during a warm-up mode in response to the pressure sensing data. The control system may monitor the pressure in the gas space and report whether the pressure in the gas space increases, indicating that the volume restricted by the separation element has decreased. In this way, movement of the separation element may be detected. The control system controlling the supply of preheated hydraulic fluid may include a monitoring program and predetermined pressure limits for performing the monitoring.

[0020] According to one embodiment, the installation comprises a dedicated control element for implementing the supply flow restriction during warm-up mode, the control element being a separate component to the control valve that controls the supply of hydraulic fluid to the impact equipment during normal operation.

[0021] In a further embodiment, the normal control valve is controlled to implement the disclosed limiting during warm-up mode and is used without this limiting function in normal operating mode.

[0022] According to one embodiment, the installation includes a dedicated warm-up supply channel or circuit for supplying preheated hydraulic fluid during warm-up, and a control element for limiting the supply is located in the warm-up supply channel. The fluid supply through the warm-up supply channel can be selected for the duration of the warm-up, and once heating is complete, the normal unlimited supply via the normal supply channel is implemented.

[0023] According to one embodiment, the control element for restricting the supply is alternatively located in connection with the normal supply channel of the impacting equipment, i.e. the supply channel that is normally used during the drilling mode to provide the required hydraulic fluid. In this solution, the control element is selectively operably connectable to restrict the flow and, accordingly, inoperably connectable so as not to affect the flow.

[0024] According to one embodiment, the first pressure accumulator is a high-pressure accumulator for storing pressurized hydraulic fluid to move the striking piston of the impact device in the impact direction. The hydraulic circuit further comprises a second pressure accumulator, a low-pressure accumulator to which a second pre-charge pressure lower than the first pre-charge pressure is applied. The control element is then configured to control the supply of pre-heated hydraulic fluid so that the pressure in the first fluid space of the first pressure accumulator is lower than the first pre-charge pressure and the pressure in the second fluid space of the second pressure accumulator is lower than the second pre-charge pressure. In other words, the impact device comprises multiple pressure accumulators, each of which includes a gas space and a fluid space. The high-pressure accumulator is the first pressure accumulator to receive the supplied fluid flow, and the low-pressure accumulator is the last pressure accumulator from which the hydraulic fluid is finally discharged from the hydraulic circuit of the impact device. The advantage of this solution is that the pressure of the preheated hydraulic fluid being supplied can be limited so that the membrane or other separating element of the high or low pressure accumulator does not move during the warm-up mode.

[0025] According to one embodiment, the pressure in the second fluid space of the low-pressure accumulator is lower than the pressure in the first fluid space of the high-pressure accumulator because of the internal flow resistance inside the impact device and because hydraulic power is used to generate the impact movement of the striking piston.

[0026] According to one embodiment, the first pre-charging pressure of the first pressure accumulator, i.e. the high pressure accumulator, is typically 50-70 bar, whereas the second pre-charging pressure of the second pressure accumulator, i.e. the low pressure accumulator, is typically 1-7 bar, depending on the performance and construction of the impact device.

[0027] According to one embodiment, the hydraulic circuit of the impact device includes a third pressure accumulator configured to receive the supplied preheated hydraulic fluid, arranged after the high pressure accumulator and in parallel with the low pressure accumulator. Thus, when testing the multiple pressure accumulators in a flow direction, the order is the first pressure accumulator, followed by the third pressure accumulator and the second pressure accumulator simultaneously. The third pressure accumulator may be a damper or stabilizer pressure accumulator, whose gas space is provided with a third precharge pressure. The control element is configured to control the supply of preheated hydraulic fluid so that the pressure in the third fluid space of the third pressure accumulator is lower than the third precharge pressure. Alternatively, the pressure in each fluid space of the multiple pressure accumulators can be set lower than the precharge pressure of the corresponding multiple pressure accumulator during warm-up. The objective may be for all separation elements of the multiple pressure accumulators to remain stationary during warm-up.

[0028] According to one embodiment, the control element is a throttle, in other words, the supply flow of preheated hydraulic fluid is throttled during the warm-up mode to reduce fluid flow through the control element to the impact device.

[0029] According to one embodiment, the throttle has a fixed orifice.

[0030] According to one embodiment, the throttle has a fixed orifice, the diameter of which is between 0.7 and 1.0 mm. A diameter of 0.8 mm was found to be suitable in one test setup.

[0031] According to one embodiment, the control element comprises at least two throttles in series, so there can be, for example, two throttles with a diameter of 1.0 mm.

[0032] According to one embodiment, the throttle is adjustable, thereby allowing the size of the throttle orifice to be varied. The orifice size may be manually or remotely adjustable.

[0033] According to one embodiment, throttling the hydraulic fluid being supplied may generate heat within the fluid, a phenomenon that can be utilized in warm-up.

[0034] According to one embodiment, the control element is a proportional valve with an adjustable orifice for throttling the preheated hydraulic fluid being supplied. In other words, this embodiment utilizes a proportional valve, which is a valve that can control fluid flow therethrough by varying the size of the orifice or flow path.

[0035] According to one embodiment, the proportional valve may be controlled under the control of a control unit belonging to the installation and controlling the warm-up mode.

[0036] According to one embodiment, any other type of adjustable valve capable of throttling or limiting the hydraulic power being provided to the impact device during warm-up may also be used.

[0037] According to one embodiment, the installation comprises at least one temperature controller or thermostat for controlling the execution of the normal operating mode. If the fluid temperature is high enough, the temperature controller can open and only then can the generation of larger shocks be allowed. Therefore, the solution may comprise one or more mechanical hydraulic temperature sensors implemented to provide temperature data for controlling the warm-up mode.

[0038] According to one embodiment, the equipment comprises at least one control unit for at least initiating and terminating the execution of a warm-up mode. In other words, the control unit is configured to automatically control the duration of the warm-up. The control unit can select the operation of the equipment between the warm-up mode and the normal drilling mode.

[0039] According to one embodiment, the control unit controls the operation of the warm-up mode and may comprise a control program, algorithm, or sequence executable in the processor of the control unit.

[0040] According to one embodiment, the control element is an adjustable element and the control unit is configured to adjust the size of the orifice of the control element to adjust the amount of restriction created in the flow being delivered.

[0041] According to one embodiment, the installation comprises at least one control unit and one or more temperature sensors for providing temperature data, and the warm-up mode is controlled in response to the temperature data. In other words, the control unit may control the start and stop of the execution of the warm-up mode and the magnitude of the warm-up in response to the collected temperature data.

[0042] According to one embodiment, the installation comprises at least one temperature sensor for determining the ambient temperature.

[0043] According to one embodiment, the installation comprises at least one temperature sensor for determining the temperature of the rock drilling machine or one of its actuators or components.

[0044] According to one embodiment, the installation comprises at least one temperature sensor for determining the temperature of the hydraulic fluid being supplied to the impact device.

[0045] According to one embodiment, the disclosed solution also relates to a rock drilling rig, comprising a mobile carrier, one or more drilling booms movably mounted relative to the carrier, at least one drilling unit mounted on the drilling booms and including a feed beam, a rock drilling machine mounted on said feed beam and including an impact equipment, and an arrangement for heating the impact equipment at low temperature operating conditions, wherein the arrangement for providing heating is according to the features and embodiments disclosed herein.

[0046] According to one embodiment, the disclosed solution also relates to a method for heating an impacting device of a rock processing machine at low temperature operating conditions, the method comprising selectively directing preheated hydraulic fluid into a hydraulic circuit of the impacting device to bring about a warm-up mode for the rock processing machine and to execute the warm-up mode before starting a normal operating mode, and directing the preheated hydraulic fluid into the hydraulic circuit of the impacting device via at least one pressure accumulator having a pre-charge pressure. The method further comprises directing the preheated hydraulic fluid into the hydraulic circuit of the impacting device through at least one control element during the warm-up mode, and limiting the supply of the preheated hydraulic fluid to the impacting device by the control element to reduce a pressure at a first pressure accumulator, the first of the at least one pressure accumulators downstream receiving the preheated hydraulic fluid, below a first pre-charge pressure of the first pressure accumulator. In other words, the magnitude of the supply of preheated hydraulic fluid is set low so that the gas space inside the one or more pressure accumulators is not compressed and so that the membrane or corresponding separating element between the gas space and the fluid space of the one or more pressure accumulators does not move during the warm-up mode.

[0047] According to one embodiment, the method includes limiting the characteristics of the preheated hydraulic fluid being directed by the control element during a warm-up mode so that the impact cycle of the impact device operates at a reduced operating frequency. Because the impact device is operating at a reduced capacity during the warm-up mode, the preheated hydraulic fluid flows through the impact device, and the preheated hydraulic fluid flowing through can effectively heat the impact device and its components, particularly the pressure accumulator. Thus, the flow of preheated hydraulic fluid enhances heat transfer, yet warm-up is gentle because the impact device and its components operate with significantly reduced hydraulic power. Heating can be more effective compared to a situation where the impact mechanism is not moving at all.

[0048] The above disclosed embodiments may be combined to form a suitable solution having the required ones of the above features.

[0049] Some embodiments are explained in more detail in the accompanying drawings. [Brief explanation of the drawings]

[0050] [Figure 1] FIG. 1 is a schematic side view of a rock drilling rig. [Figure 2] 1 is a schematic diagram of a hydraulic rock drilling machine. [Figure 3] 1 is a schematic diagram of an installation for preheating impact equipment. FIG. [Figure 4] FIG. 2 is a schematic diagram of a pressure accumulator connected to the hydraulic circuit of the impact device. [Figure 5] 1 is a schematic diagram of a pressure accumulator and the movement of a separation element due to a pressure difference within its pressure space. [Figure 6] 1 is a schematic side view of a work machine equipped with a hydraulic crushing hammer. DETAILED DESCRIPTION OF THE INVENTION

[0051] For clarity, the figures show some embodiments of the disclosed solution in a simplified manner.In the drawings, like reference numerals denote like elements.

[0052] FIG. 1 shows a rock drilling rig 1 intended for surface drilling. The rock drilling rig 1 comprises a mobile carrier 2 and at least one drilling boom 3 connected to the carrier 2. At the distal end of the drilling boom 3 is a drilling unit 4 comprising a feed beam 5 and a rock drilling machine 6 supported thereon. A drilling tool 7 can be connected to the drilling machine 6. The rock drilling machine 6 may comprise a shank adapter 8 at its front end for connecting the tool 7. The rock drilling machine 6 comprises an impact device 9 and a rotary device 10. The rock drilling machine 6 can be moved on the feed beam 5 by means of a feed device 11. The rock drilling machine 6 is hydraulically operated and is connected to a hydraulic system HS. When starting operation in cold temperatures, the hydraulic fluid of the hydraulic system HS and the hydraulic rock drilling machine 6 need to be preheated before the actual drilling process can begin. If not properly preheated, there is a risk of damage to the components of the impact device 9. Therefore, the disclosed rock drilling rig 1 may comprise the disclosed preheating facility.

[0053] Figure 2 discloses a rock drilling machine 6, which is one type of rock processing machine Rtm. The rock drilling machine comprises a body 12, an impact device 9, a rotating device 10, a flushing housing 13, a shank adapter 8, and a gear housing 14 attached to the front end of the body 12. The impact device 9 comprises an impact piston for generating an impact pulse in the shank adapter 8. The piston reciprocates in an impact direction and a return direction.

[0054] 2 also shows a first pressure accumulator Pa1 and a second pressure accumulator Pa2 that are part of the hydraulic circuit of the impact device 9. The first pressure accumulator Pa1 may be a high-pressure accumulator, and the second pressure accumulator Pa2 may be a low-pressure accumulator. The pressure accumulators Pa1 and Pa2 store and release pressurized hydraulic pressure according to the movement of the impact piston.

[0055] FIG. 3 shows, in a simplified hydraulic diagram, an arrangement in which preheated hydraulic fluid can be circulated through the impact device 9 in a gently restricted manner when the warm-up mode WM is activated in the control unit CU. The hydraulic fluid can be preheated by a preheating device 15, which may comprise a heating means connected to a tank 16, or the preheating device 15 can circulate the hydraulic fluid through a hydraulic throttle to heat it. The preheating device 15 can be controlled by the control unit CU. A hydraulic pump 17 pumps the hydraulic fluid through a hydraulic circuit 18 through the impact device 9 and back to the tank 16. During the warm-up mode WM, the hydraulic fluid is delivered to the supply port 20 of the impact device 9 via a supply channel 19 and through the control element CE by the control valve CV. The control element CE restricts the supply of preheated hydraulic fluid so that the striking piston 21 performs a reciprocating movement at a lower impact speed and pressurizes the first and second pressure accumulators Pa1 and Pa2 below the pre-charge pressure. The preheated hydraulic fluid flows gently inside the impact device 9, preventing excessive stress on the cold structure. The preheated fluid passes through the hydraulic channels inside the impact device 9, allowing the heat of the preheated fluid to dissipate effectively. Finally, the hydraulic fluid flow is discharged through the outlet port 22. When the normal mode NM is engaged, preheating ends, and the control valve CV directs the fluid flow through the channel 23 through the control element CE. In the normal mode NM, the fluid flow is not restricted, allowing the impact device 9 to operate at its designed impact speed and allowing the pressure accumulators Pa1 and Pa2 to experience greater pressure inside their fluid spaces. The first pressure accumulator Pa1 assists the movement of the striking piston 21 in the impact direction A, while the second pressure accumulator Pa2 assists its movement in the return direction B.

[0056] The hydraulic connection of the control valve CV, the channel 23 and the control element CE can of course differ from the exemplary solution shown in FIG.

[0057] The control unit CU may include a processor for executing one or more control programs including a control principle for controlling at least the control element CE, the control valve CV, and the preheating device 15. The control unit CU may be arranged to control the disclosed installation automatically or with the assistance of an operator. A user interface UI may be present for communication between the control unit CU and an operator. The control unit CU may receive temperature data from one or more temperature sensors TS. There may be one or more temperature sensors TS for sensing ambient temperature, hydraulic fluid temperature, and component temperature. The temperature data received by the control unit CU may be taken into account when controlling the operating mode between a normal mode NM and a warm-up mode WM.

[0058] The control unit CU may also be configured to control the operation of the hydraulic pump 17. The control unit CU may impose lower fluid flow and pressure requirements on the hydraulic pump 17 during the warm-up mode WM. The hydraulic pump 17 may, for example, be equipped with an adjustable volume capacity.

[0059] 3 further discloses several embodiments of a control element CE that can be attached to the supply channel 19. The control element CE can be a throttle 24 with either a fixed orifice 24a or an adjustable orifice 24b. Alternatively, the control element CE can be a proportional valve 25 with an adjustable opening for throttling the preheated hydraulic fluid being supplied. The proportional valve 25 can be electrically controlled under the control of the control unit CU.

[0060] 3 does not disclose a control valve for controlling the operating cycle of the striking piston 21 of the impact device 9. The control valve may be, for example, a sleeve structure surrounding the striking piston 21.

[0061] FIG. 4 shows two consecutive hydraulic actuators Pa1 and Pa2 arranged in the hydraulic circuit 18 of the impact device. The supply channel 19 is equipped with a control element CE for limiting the flow, pressure, or flow and pressure of the preheated hydraulic fluid supplied during the warm-up mode. The control element limits the supply so that the hydraulic fluid pressure Fp1 in the first pressure accumulator Pa1, which is located first downstream of the supplied flow, is lower than the first pre-charge pressure Pcp1 in the gas space GS of the first pressure accumulator Pa1. The pressure Fp1 prevails in the fluid space Fs1 of the first pressure accumulator Pa1. As the hydraulic fluid flows through the impact device and hydraulic energy is utilized to perform the reciprocating motion of the striking piston, the hydraulic fluid pressure Fp2 in the second pressure accumulator Pa2 is lower. The first pressure accumulator Pa1 is a high-pressure accumulator for storing pressurized hydraulic fluid to execute movement of the striking piston in the impact direction, and the second pressure accumulator Pa2 is a low-pressure accumulator provided with a second pre-charge pressure Pcp2 lower than the first pre-charge pressure Pcp1. The control element CE is also configured to control the supply of pre-heated hydraulic fluid so that the hydraulic fluid pressure Fp2 in the second fluid space Fs2 of the second pressure accumulator Pa2 is lower than the second pre-charge pressure Pcp2. The pressures Fp1 and Fp2 do not cause movement of the separation elements Se1 and Se2, thereby allowing gentle heating to be provided to the pressure accumulators Pa1 and Pa2.

[0062] In some hydraulic circuits of impact equipment there may be only one pressure accumulator, in others there may be three or more pressure accumulators, and the same principle for the supply of preheated hydraulic fluid also applies.

[0063] FIG. 5 shows a pressure accumulator Pa connected to the hydraulic circuit 18, through which preheated hydraulic fluid is supplied via a control element CE controlled by a control unit CU. A pre-fill pressure can be set in the gas space Gs through a gas port 26. A separation element Se, such as a membrane, can move 27 from the fluid space Fs toward the gas space Gs when the pressure inside the fluid space Fs is greater than the pressure inside the gas space Gs. This movement 27 of the separation element Se can be detected by sensing the pressure Psg inside the gas space Gs. If the pressure in the gas space Gs increases, it means that the separation element Se' has moved. The pressure Psf prevailing inside the fluid space Fs can also be sensed. The control unit CU can take the collected pressure data into account when controlling the operation of the control element CE.

[0064] Figure 6 discloses a mobile work machine 27 comprising a boom 28 and a hydraulic rock breaking hammer 29 attached to the boom 28. The rock breaking hammer 29 is a rock processing machine Rtm comprising an impact device 9 configured to apply impact pulses to a breaking tool 30 for breaking rock material. The impact device 9 is connected to a hydraulic system HS with the disclosed provisions for pre-heating the impact device 9 if necessary.

[0065] The drawings and associated description are intended only to illustrate the concepts of the invention, which may vary in its details within the scope of the claims.

Claims

1. 1. An installation for heating hydraulic impact equipment (9) of a rock processing machine (Rtm) at low temperature operating conditions, comprising: a selectively operable warm-up mode (WM) for supplying preheated hydraulic fluid to the hydraulic circuit (18) of said impact device (9) through at least one supply channel (19); the hydraulic circuit (18) of the impact device (9) is connected to at least one pressure accumulator (Pa) to which a pre-charging pressure (Pcp) is applied; In the equipment, the supply channel (19) comprises at least one control element (CE) for limiting the supply of the preheated hydraulic fluid in response to the warm-up mode (WM) being selected; The control element (CE) is configured to limit the supply of the preheated hydraulic fluid in the supply channel (19) so that its pressure is below a first pre-charge pressure (Pcp1) of a first pressure accumulator (Pa1) located first downstream in the supplied flow. characterized in that Equipment.

2. the first pressure accumulator (Pa1) is a high-pressure accumulator for storing pressurized hydraulic fluid to effect a movement in the impact direction (A) of the striking piston (21) of the impact device (9); the hydraulic circuit (18) further includes a second pressure accumulator (Pa2) that is a low-pressure accumulator provided with a second pre-charge pressure (Pcp2) that is lower than the first pre-charge pressure (Pcp1); The control element (CE) is configured to control the supply of the preheated hydraulic fluid so that the pressure in the first fluid space (Fs1) of the first pressure accumulator (Pa1) is lower than the first pre-charge pressure (Pcp1) and the pressure in the second fluid space (Fs2) of the second pressure accumulator (Pa2) is lower than the second pre-charge pressure (Pcp2).

2. The installation according to claim 1 , characterized in that

3. The control element (CE) is a throttle (24).

2. The installation according to claim 1 , characterized in that

4. The control element (CE) is a proportional valve (25) with an adjustable opening for throttling the supplied preheated hydraulic fluid.

2. The installation according to claim 1 , characterized in that

5. at least one control unit (CU) for at least initiating and terminating the execution of said warm-up mode (WM); 2. The installation according to claim 1 , characterized in that

6. at least one control unit (CU); further comprising at least one temperature sensor (TS) for providing temperature data; The warm-up mode (WM) is controlled in response to the temperature data.

2. The installation according to claim 1 , characterized in that

7. a movable carrier (2); at least one excavating boom (3) movably mounted relative to said carrier (2); at least one drilling unit (4) attached to said at least one drilling boom (3) and including a supply beam (5); a rock drilling machine (6) mounted on said supply beam (5) and including an impact device (9); a facility for heating said impact device (9) at low temperature operating conditions; A rock drilling rig (1) comprising: The facility is a facility according to any one of claims 1 to 6. A rock drilling rig (1).

8. 1. A method for heating an impact device (9) of a rock processing machine (Rtm) at low temperature operating conditions, comprising: selectively directing preheated hydraulic fluid into a hydraulic circuit (18) of said impacting device (9) to bring said rock processing machine (Rtm) into a warm-up mode (WM) and to perform said warm-up mode (WM) before initiating a normal operating mode (NM); conducting said preheated hydraulic fluid into the hydraulic circuit (18) of said impact device (9) through at least one pressure accumulator (Pa) provided with a pre-charge pressure (Pcp); Including, conducting the preheated hydraulic fluid through at least one control element (CE) into the hydraulic circuit (18) of the impact device (9) during the warm-up mode; limiting the supply of the preheated hydraulic fluid to an impact device (9) by the control element (CE) to reduce the pressure in a first pressure accumulator (Pa1), the first of the at least one pressure accumulators receiving the preheated hydraulic fluid downstream, below a first pre-charge pressure (Pcp1) of the first pressure accumulator (Pa1); A method characterized by:

9. During the warm-up mode (WM), the control element (CE) limits the characteristics of the preheated hydraulic fluid being conducted so that the impact cycle of the impact device (9) operates at a reduced operating frequency.

9. The method according to claim 8.

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