EP4665978A1

EP4665978A1 - A dosing pump

Info

Publication number: EP4665978A1
Application number: EP23708044.5A
Authority: EP
Inventors: Ulf Persson; Tobias ANHAMMER
Original assignee: Epiroc Rock Drills AB
Current assignee: Epiroc Rock Drills AB
Priority date: 2023-02-14
Filing date: 2023-02-14
Publication date: 2025-12-24
Also published as: WO2024172704A1

Abstract

The present disclosure relates to a dosing pump (101), for dosing a liquid composition. The dosing pump (101) comprises at least a first and a second cylinder compartment (102, 121) fluidly separated from one another, a first piston (103), a second piston (122), a first piston rod portion (104) and a second piston rod portion (123). The first cylinder compartment (102) is configured for filling and dosing the liquid composition. The dosing pump (101) facilitates an accurate dosing of a liquid composition. The dosing pump (101) may be a dosing pump (101) for grouting. The present disclosure further relates to a grouting system (171), a rig, a computer-implemented method for determining a weight of a liquid composition and a computer program product.

Description

A DOSING PUMP

TECHNICAL FIELD

The present disclosure relates to a dosing pump, a grouting system and a rig. It further relates to a computer-implemented method and a computer program product.

BACKGROUND

In mining and civil engineering grouting is used for water proofing and/or stabilizing the ground or rock. For water proofing, a grouting material is filled into boreholes or cracks in the rock. The grouting mixture is a mixture of cement and water, and an additive for curing the grouting mixture is usually required. Further, rock bolt reinforcement is commonly used for providing support to the roof or sides of a cavity in underground mining. The bolt may be a steel rod, a rebar or a cable bolt. The bolt may be installed in a borehole drilled into the roof or walls of a rock formation and a grouting mixture is used for fastening the bolt. The bolt may be inserted in a borehole before or after filling the borehole with the grouting material.

Usually, grouting requires adding different kinds of additives to the grouting mixture. The recipe of grouting mixtures varies depending on several factors, such as rock conditions, water/cement ratio and other variables. The time for mixing the grouting material is important for the process of grouting. The grouting material needs to cure fast enough to provide a sufficient support strength. Further, when a bolt is to be inserted to a borehole, the curing needs to be slow enough to remain pumpable for sufficient time to fill the borehole. The speed of curing further needs to ensure sufficient time for inserting the bolt in the borehole.

The recipe of the grouting material is important, as well as the time for mixing the grouting material. Large amounts of water and cement is used in the grouting material, and the predefined amount of additive is important for the grouting quality. It is important to add the correct amount of additive which is a quite small share of the total amount of grouting material. Thus, there is a desire to provide a grouting material according to a specific recipe with repeatable accuracy in a time efficient and cost-effective manner. SUMMARY

The present disclosure intends to provide an in at least some aspect improved solution for providing an effective and accurate dosing of an additive in a time efficient and cost- effective manner.

According to a first aspect, the present disclosure provides a dosing pump for dosing a liquid composition according to claim 1. The dosing pump comprises at least a first and a second cylinder compartment fluidly separated from one another, a first piston, a second piston, a first piston rod portion and a second piston rod portion. The first cylinder compartment is configured for filling and dosing the liquid composition. Further, the first piston is arranged in the first cylinder compartment and the second piston is arranged in the second cylinder compartment between the first piston rod portion and the second piston rod portion. The first piston rod portion mechanically connects the first piston to the second piston, whereby the first and second pistons are arranged for common movement along an axial direction. The first cylinder compartment comprises an inlet and an outlet for the liquid composition and an opening for air breathing. The first piston is arranged to induce a flow of the liquid composition to/from the first cylinder compartment via the inlet and the outlet, respectively, and the second cylinder compartment is fluidly connectable to a hydraulic pump for hydraulically controlling the common movement of the first and second pistons along the axial direction. The first piston rod portion and the second piston rod portion have the same cross-sectional area, and the total length of the second piston and the second piston rod portion along the axial direction corresponds to at least a length of the second cylinder compartment.

The second piston together with the first rod portion and/or the second rod portion will at all times occupy an identical space within the second cylinder compartment, regardless of the axial position of the piston. The first rod portion and the second rod portion have the same cross-section area and therefore together with the piston occupy the same volume regardless of the axial position of the piston. The dosing pump will therefore, during use, have a constant volume of hydraulic fluid provided within the second cylinder compartment and thereby dosing of the liquid composition will be facilitated. The second cylinder compartment is occupied by an identical space of the second piston together with the first rod portion and/or the second rod portion regardless of the axial position of the piston. The second cylinder compartment will thereby, during use, be provided with a constant volume of hydraulic fluid and thus will be provided with a constant weight of the hydraulic fluid. Thanks to the constant weight of the hydraulic fluid, it is only the weight of the liquid composition that will vary during dosing which facilitates the dosing of the liquid composition.

Optionally, the first piston rod portion may extend through a first wall separating the first cylinder compartment from the second cylinder compartment, wherein the first wall is arranged in a second cylinder compartment first end.

Optionally, the second piston rod portion may extend through a second wall arranged in a second cylinder compartment second end. The second cylinder compartment second end is herein arranged opposite to the second cylinder compartment first end.

Optionally, the first piston rod portion and the second piston rod portion may have a constant cross-sectional area in the longitudinal direction, i.e. along the axial direction. The cross-sections of the first and second rod portions, respectively, preferably have the same shape along the length of the respective rod portion. The first and second rod portions may be formed as cylinders, such as circular cylinders or rectangular cuboids, or similar.

The first rod portion and the second rod portion may be separate parts, or they may be portions of the same rod, extending from opposite ends of the second piston.

Optionally, the hydraulic fluid may be a liquid.

Optionally the hydraulic fluid may be an oil.

Optionally, the second cylinder compartment may comprise a first port and a second port that are configured to be connected to a hydraulic pump. A hydraulic pump connected to the second cylinder compartment may facilitate the adjustment of the hydraulic flow in the second cylinder compartment.

Optionally, the first port may be arranged at a second cylinder compartment first end, and the second port may be arranged at a second cylinder compartment second end. Optionally, each one of the ports may be configured to alternatively receive hydraulic fluid and alternatively dispatch hydraulic fluid. The fluid may be transported to and from the hydraulic pump through the ports in either direction depending on if the liquid composition is received or dispatched.

Optionally, the dosing pump may comprise a load cell configured to measure a weight of the dosing pump. A load cell may facilitate the weighing of the dosing pump. The load cell may sense the change of the weight of the dosing pump and may thereby indicate the weight of the liquid composition that may be introduced to the dosing pump.

Optionally, the dosing pump may comprise a third cylinder compartment arranged for protecting the second piston rod portion. When the second piston rod extends outside the second cylinder compartment it may be an advantage to protect the second piston rod portion from the outside environment and from possible collision with devices which are close to the dosing pump.

Optionally, the third cylinder compartment may be arranged next to the second cylinder compartment outside of the second wall.

Optionally, the liquid composition may comprise an additive. The additive may be an accelerator, a catalyst, a cross-linking agent or a plasticiser for example. The amount of such an additive may be dosed with high accuracy with the dosing pump.

Optionally, the dosing pump may be a dosing pump for grouting. A grouting composition may comprise an additive in a certain amount for giving the grouting composition accurate properties at a proper occasion during the grouting procedure. This may be achieved with the dosing pump.

According to a second aspect, the present disclosure provides a grouting system configured to inject a grouting mixture comprising a liquid composition into a bore hole, the grouting system comprising at least one dosing pump according to the first aspect for dosing the liquid composition. When grouting is performed, it is important that an accurate amount of liquid composition is added to the grouting mixture. The grouting mixture may be injected into a bore hole and it may be important that the grouting mixture is solidified in a certain time. It may thus be important to add a correct amount of liquid composition which may be achieved by the grouting system.

According to a third aspect, the present disclosure comprises a rig comprising a grouting system according to the second aspect. A rig may be an equipment intended for earth surface use or underground use. A grouting system comprising a dosing pump may improve any mining operations or construction work when an accurate amount of liquid composition may be dosed with the dosing pump comprised in the rig.

According to a fourth aspect, the present disclosure comprises a computer-implemented method for determining a weight of a liquid composition using the dosing pump according to the first aspect. The method comprises: in a processor device of a control system, receiving weight data from a load cell configured to measure a weight of the dosing pump, the weight data being indicative of the weight of the dosing pump while the liquid composition is being delivered to the first cylinder compartment, and in the processor device, determining the weight of the liquid composition based on the received weight data.

The method may improve the possibility to weigh a liquid composition in an accurate amount in a facilitated way.

Optionally, the computer-implemented method may comprise: in the processor device, receiving weight data from the load cell, the weight data being indicative of a weight of the dosing pump without the liquid composition present in the first cylinder compartment, wherein determination of the weight of the dosing pump is determined in the processor device based on the received weight data, and in the processor device, receiving weight data from the load cell, the weight data being indicative of a weigh of the dosing pump comprising the liquid composition, wherein the weight of the dosing pump comprising the liquid composition is determined in the processor device based on the received weight data, and

- wherein the weight of the dosing pump without the liquid composition is subtracted from the weight of the dosing pump comprising the liquid composition. A method for further improving the possibility to weigh a liquid composition in an accurate amount is obtained.

According to a fifth aspect, the present disclosure comprises a computer program product comprising instructions which, when executed on a processor device, cause the processor device to carry out the method according to the fourth aspect. A computer program product facilitates the computer-implemented method.

Further advantages and advantageous features of the disclosure are disclosed in the following description and in the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will be further explained hereinafter by means of non-limiting examples and with reference to the appended drawings, wherein:

Figure 1 shows a dosing pump as disclosed herein, in a stage wherein no liquid composition is added to the dosing pump.

Figure 2 shows a dosing pump as disclosed herein, in a stage wherein the dosing pump is partly filled with liquid composition.

Figure 3 shows a dosing pump as disclosed herein, in a stage wherein the dosing pump is filled with liquid composition.

Figure 4 shows an embodiment of a dosing pump as disclosed herein, in a stage wherein the dosing pump is partly filled with liquid composition.

Figure 5 shows an embodiment of a dosing pump as disclosed herein, wherein a load cell is shown with the dosing pump.

Figure 6 shows a grouting system as disclosed herein.

Figure 7 is a flow chart illustrating a method according to the disclosure.

The drawings are schematic and not necessarily drawn to scale. All reference numbers are not necessarily shown in all figures.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The dosing pump according to the disclosure may be used for weighing a certain amount of a liquid composition. The liquid composition may comprise an additive, for example a catalyst, an accelerator, a cross-linking agent or a plasticiser. The liquid composition could be added to a mixture, wherein it is important that the accurate amount of liquid composition is added in relation to the other components of the mixture. The dosing pump according to the disclosure has the advantage that it is only the weight of the liquid composition which varies or alters during the process of weighing and measuring the amount of liquid composition. Further, the dosing pump may act both as a pump and a vessel for the liquid composition. The dosing pump repeatedly weighs an accurate amount of liquid composition to be dosed, and this is made without increasing mixing time when the liquid composition is added to a mixture by use of the dosing pump. Fewer parts are needed for the dosing, since the dosing element also works as a vessel.

There may be a difficulty when dosing a small amount of a liquid. A difficulty may be that it is only the weight of the component which should be dosed which is desired to be measured. This problem may be solved with the present disclosure.

A dosing pump 101 for dosing a liquid composition as disclosed herein is shown in figures 1, 2, 3 and 4. Figures 1-3 show the dosing pump 101 according to the disclosure in different stages. When the compartments or parts of the compartments comprise liquid, the compartments or part of compartments are marked as dotted areas as can be seen in figure 1-3 and in figure 4.

The dosing pump 101 comprises at least a first and a second cylinder compartment 102, 121 fluidly separated from one another. The dosing pump 101 further comprises a first piston 103 and a second piston 122. The first piston 103 is connected to a first piston rod portion 104 and the second piston 122 is connected to a second piston rod portion 123. The first cylinder compartment 102 is configured for filling and dosing the liquid composition. Further, the first piston 103 is arranged in the first cylinder compartment 102 and the second piston 122 is arranged in the second cylinder compartment 121 between the first and second piston rod portions 104, 123. The first piston rod portion 104 is mechanically connecting the first piston 103 to the second piston 122, whereby the first and second piston portions 103, 122 are arranged for common movement along an axial direction Z. The first cylinder compartment 102 comprises an inlet 105 and outlet 106 for the liquid composition and an opening 107 for air breathing. The first piston 103 is arranged to induce a flow of the liquid composition to/from the first cylinder compartment 102 via the inlet 105 and the outlet 106, respectively. The second cylinder compartment 121 is fluidly connectable to a hydraulic pump (not shown in figures 1-4) for hydraulically controlling the common movement of the first and second pistons 103, 122 along the axial direction Z. The first piston rod portion 104 and the second piston rod portion 123 have the same cross-sectional area. Since the first piston rod portion 104 and the second piston rod portion 123 have the same cross-sectional area, the volume occupied by one or both of the piston rod portions 104, 123 in the second cylinder compartment 121 will be the same irrespective of where the second piston 122 is located at the moment. This also means that the volume and weight of the hydraulic fluid in the second cylinder compartment 121 will be constant during use. Further, the weight of the dosing pump 101 when including only the hydraulic fluid will be constant during use. Thus, when inserting the liquid composition to the dosing pump 101 and weighing the liquid composition, the only component that will vary in weight during the use of the dosing pump 101 , is the liquid composition. It is therefore possible to only measure the change of weight of the liquid composition during dosing of the liquid composition. Measuring an accurate weight of the liquid composition may then be facilitated.

The dosing pump 101 may comprise a first wall 110 separating the first cylinder compartment 102 from the second cylinder compartment 121. The first wall 110 may be arranged in the second cylinder compartment first end 127. The first wall 110 may also be arranged in the first cylinder compartment second end 109. The first cylinder compartment second end 109 and the second cylinder compartment first end 127 may coincide in the first wall 110. Further, the first cylinder compartment 102 may comprise a third wall 111 arranged in a first cylinder compartment first end 108. The dosing pump 101 may have a fourth wall 142 arranged in a third cylinder compartment second end 143.

A second wall 124 may be arranged in the second cylinder compartment second end 128.

The second piston rod portion 123 may in this context also be called a dummy piston rod portion. The second piston rod portion 123, or the dummy piston rod portion, does have the task to occupy volume of the hydraulic fluid in the second cylinder compartment 121 during use. The volume, which is occupied by the second piston rod portion 123, would, if the second piston rod portion 123 was not arranged in the second cylinder compartment 121 , be occupied by the hydraulic fluid and the volume of hydraulic fluid would change during the movement of the second piston 122. Further, the total length L_tot of the second piston 122 and the second piston rod portion 123, along the axial direction Z, has at least a length L of the second cylinder compartment 121. As measured along the axial direction, the total length L_tot of the second piston 122 and of the second piston rod portion 123 needs to be at least the length L of the second cylinder compartment 121 since otherwise the second piston rod portion 123 would not be able to occupy the whole length of the second cylinder compartment 121, extending from the second piston 122 to a second wall 124 of the dosing pump 101. The second wall 124 is arranged in a second cylinder compartment second end 128 which will be referred to below. Further, the second piston rod portion 123 needs to extend through the second wall 124. The second piston rod portion 123 needs to close a hole of the second wall 124 through which the second piston rod portion 123 is extending, so that the hydraulic fluid will remain in the second cylinder compartment 121.

According to embodiments as shown in figures 1, 2, 3 or 4, the first piston rod portion 104 extends through a first wall 110 separating the first cylinder compartment 102 from the second cylinder compartment 121, wherein the first wall 110 is arranged in a second cylinder compartment first end 127. Further, the first wall 110 may contain a seal for sealing between the first wall 110 and the first piston rod portion 104. This will reduce the risk that hydraulic fluid leaks out through the first wall 110. The seal may be a gasket or an O-ring for example.

Further, according to the embodiment as shown in figures 1 , 2, 3 or 4, the second piston rod portion 123 extends through the second wall 124 arranged in a second cylinder compartment second end 128. Further, the second wall 124 may contain a seal for sealing between the second wall 124 and the second piston rod portion 123. This will reduce the risk that hydraulic fluid leaks out through the second wall 124. The seal may be a gasket or an O-ring for example.

The first piston rod portion 102 and the second piston rod portion 121 may have a constant cross-sectional area in the longitudinal direction, i.e. along the axial direction Z.

Further, the first rod portion 104 and the second rod portion 123 may be separate parts, or they may be portions of the same rod, extending from opposite ends of the second piston 122. The hydraulic fluid may be a liquid. Further, the hydraulic fluid may be an oil.

The second cylinder compartment 121 may comprise a first port 125 and a second port 126 configured to be connected to a hydraulic pump 158 (shown in figure 5). The hydraulic pump may be used for regulating the flow of hydraulic fluid to and from the second cylinder compartment 121.

The first port 125 may be arranged at a second cylinder compartment first end 127, and the second port 126 may be arranged at a second cylinder compartment second end 128.

The ports 125, 126 are herein configured to alternatively receive hydraulic fluid and alternatively dispatch hydraulic fluid. An embodiment of a dosing pump 101 is shown in figure 2 and in the dosing pump 101 of figure 2, the second piston 122 is arranged in about the middle of the second cylinder compartment 121 . The first port 125 is arranged adjacent the first wall 110 and the second port 126 is arranged adjacent the second wall 124.

The flow of the hydraulic fluid will make the pistons 103, 122 move together back and forth along the axial direction Z. The piston movement will either suck the liquid composition into the first cylinder compartment 102 or push it out.

Further, the dosing pump 101 may comprise a third cylinder compartment 141 arranged for protecting the second piston rod portion 123. The third cylinder compartment 141 may be arranged next to the second cylinder compartment 121 , outside of the second wall 124. The third cylinder compartment 141 is optional, but is shown in figures 1-3. Figure 4 shows an embodiment that does not comprise any third cylinder compartment, but otherwise comprises the same components as disclosed in figures 1-3.

It is referred to figures 1 , 2 and 3 for illustrating the process of dosing a liquid composition with the dosing pump 101.

It is referred to figure 1 which shows a dosing pump 101 which is in a stage when the first cylinder compartment 102 does not contain any liquid composition. The first piston 103 is at this stage located at the third wall 111 in the first cylinder compartment first end 108. No liquid composition is filled to the first cylinder compartment 102. The first cylinder compartment 102 does not contain any liquid, but is filled with air. The air may be entered through the opening 107 while the liquid composition is discharged, or air may be discharged through the opening 107 if the liquid composition is introduced into the first cylinder compartment 102. The movement of the first piston 103 will either force the air to be discharged by the movement in the direction towards the first wall 110 or make the air enter the first cylinder compartment 102 by the movement of the first piston 103 in the direction towards the first cylinder compartment first end 108. In the embodiment of figure 1, the second piston 122 is located at the first wall 110. The second cylinder compartment

121 is completely filled with hydraulic fluid. The second piston 122 and the second piston rod portion 123 is occupying a volume within the second cylinder compartment 121. The second piston rod portion 123 extends from the second piston 122 and through the second wall 124. The total length L_tot of the second piston 122 and the second piston rod portion 123 along the axial direction has at least a length L of the second cylinder compartment 121.

Figure 2 shows the dosing pump 101 in a stage wherein some liquid composition has been received or introduced into the first cylinder compartment 102. The hydraulic pump will hydraulically control the common movement of the first and second pistons 103, 122. Thus, when hydraulic fluid is entering the first port 125 the pistons 103, 122 are moved in the direction from the first wall 110 to the second wall 124, while the hydraulic fluid will be discharged through the second port 126. When the second piston 122 is moved by the hydraulic control in the second cylinder compartment 121, the first piston 103 is moved at the same time. The first piston rod portion 104 is mechanically connecting the first piston 103 to the second piston 122 and they will thus move simultaneously and in the same direction and with the same distance. While further hydraulic fluid is entering the first port 125 of the second cylinder compartment 121 , the first piston 103 and the second piston

122 will move in the direction towards the second wall 124 and liquid composition will enter the first cylinder compartment 102 until the desired weight of liquid composition has been received into the first cylinder compartment 102. The movement of the first piston 103 and the second piston 122 is controlled by the hydraulic flow regulated by the hydraulic pump 158. The pump 158 is controlled from a control unit and thereby controls if the hydraulic fluid is entering the first port 125 or entering the second port 126 and if the hydraulic fluid thereby is discharged from the first port 125 or is discharged from the second port 126. Figure 3 shows a dosing pump 101 in a stage wherein the first cylinder compartment 102 is completely filled with liquid composition. The first piston 103 is located at the first wall 110. The second piston 122 is located at the second wall 124. When the first piston 103 together with the second piston 122 have been moved to the first and second walls 110, 124, liquid composition has been introduced via the inlet 105 and the hydraulic fluid has been introduced through the first port 125 and discharged through the second port 126.

The whole second cylinder compartment 121 is filled with hydraulic fluid at all stages during use.

The first cylinder compartment 102 to be filled with liquid composition does not need to be completely filled. A control system may stop the entering of the liquid composition at any time when the desired weight of liquid composition is obtained.

The first piston rod portion 104 and the second piston rod portion 123 have the same cross-sectional area. This means that the second piston 122 together with the part of the first piston rod portion 104 and the part of the second piston rod portion 123 that occupy the second cylinder compartment 121 will always occupy the same volume. The second cylinder compartment 121 is always occupied by the second piston 122. Thus, in figure 1, the second cylinder compartment 121 is occupied by the second piston 122 and the second piston rod portion 123. In figure 3, the second cylinder compartment 121 is occupied by the second piston 122 and the first piston rod portion 104. In figure 2, the second cylinder compartment 121 is occupied by the second piston 122 and a part of the first piston rod portion 104 and a part of the second piston rod portion 123. The parts of the first and second piston rod portions 104, 123 will always occupy the same total length and thereby also the same volume. Thus, the second cylinder compartment 121 will always be occupied by the same volume of the second piston 122 and a piston rod portion or parts of two piston rod portions 104, 123. Thus, the volume of the hydraulic fluid will always be the same in the second cylinder compartment 121 during use.

As also mentioned, the second cylinder compartment 121 is always filled completely with hydraulic fluid during use. The dosing pump 101 may comprise or be connectable to a load cell 151 for measuring the weight of the dosing pump 101. A dosing pump 101 comprising a load cell 151 is shown in figure 5. The dosing pump 101, shown schematically in figure 5, may e.g. have the configuration shown in figures 1-3 or figure 4.

The load cell 151 may be arranged on or attached to an outer surface or outer wall of the dosing pump 101. The load cell 151 may be attached by an attachment device 152. The load cell 151 may further be connected to a connection device 157. The load cell 151 may be electrically connected to weighing instruments in a control system. The control system may read load signals from the load cell 151. The load will be read and compared to a predetermined value. The inlet 105 may be connected to a liquid composition tank 153, from which liquid composition tank 153 the liquid composition is received. The inlet 105 may be connected from the liquid composition tank 153 via a suction hose 154. From the outlet 106 may an outlet hose 155 be arranged and connected to a mixer 156 for mixing the liquid composition with further components. The load cell 151 may be arranged on a connection device 157, which may be attached to an arrangement or a rig which will be referred to below. The load cell 151 may alternatively be attached to the outer surface of the dosing pump 101 at the second wall 124 or at the fourth wall 142, and thus the dosing pump would be hanging down from the load cell 151.

The dosing pump 101 may be a dosing pump 101 for grouting.

Grouting is performed for water proofing and/or stabilizing the ground or the rock. A grouting mixture may comprise cement, water and a liquid composition, which is injected to a bore hole for example. The liquid composition may comprise an additive, such as an accelerator, a catalyst, a cross-linking agent or a plasticiser.

Large amounts of water and cement is used in grouting material. A predefined amount of additive is important for the grouting quality. A correct amount of additive which is a quite small amount of the total amount of grouting material is added to the grouting material. Thus, there is a desire to provide a grouting material according to a specific recipe with repeatable accuracy in a time efficient time and cost-effective manner.

The addition of additives in grouting mixtures is made with a specific and predefined amount. The time for addition of an additive may be important and it is important that the amount of additive is accurate. A grouting composition may comprise cement, water and a liquid composition. The liquid composition may comprise an additive, such as an accelerator, a catalyst, a cross-linking agent or a plasticiser. The amount of liquid composition is quite small compared to the amount of cement and water. It is therefore important that the accurate amount of liquid composition is added to the grouting mixture. With the dosing pump 101 for grouting, the grouting process may be facilitated. The dosing pump 101 may work both as a pump and a vessel, and less components are needed for the grouting process. Further, the need of an air compressor may be reduced.

The present disclosure further provides a grouting system 171 configured to inject a grouting mixture comprising a liquid composition into a bore hole 181. The grouting system 171 comprises at least one dosing pump 101 as disclosed herein.

The system may further comprise a water supply 173, a cement supply 174, a mixing device 175 and a pumping device 176. The water supply 173 and the dosing pump 101 may be connected to the mixing device 175 via a connecting pipe 184.

A grouting system 171 is shown in figure 6. A dosing pump 101 is shown which provides the liquid composition to a mixing device 175. Dry cement may be stored and contained in a cement silo 172 and the cement may be loaded by a cement supply 174, which may be a feed screw feeding mixer, to the mixing device 175. Water may be supplied from a water supply 173, such as a water inlet hose. A grouting mixture may be transported from the mixing device 175 to a pumping device 176 via a grouting mixture hose 177. Then the grouting mixture may further be transported under pressure via a second hose 179 to a bore hole 181. The bore hole 181 can for example be drilled in a rock 180. A packer 182 may be used for stopping the injected grouting mixture 183 to move backwards from the bore hole 181. When grouting mixture is injected, the packer 182 will swell and hinder backwards movement of the grouting mixture 183. The grouting mixture 183 will solidify in the bore hole 181.

More than one dosing pump 101 may be comprised in a grouting system. More than one additive may be used for a grouting system and could be added by two separate dosing pumps for example. Additional load cells (not shown) may be electrically connected to weighing instruments in a control system. The control system may read load signals from load cells. A load cell may be connectable to the mixing device for weighing the amount of water supplied to the mixing device. Further, the load cell may be connectable to the mixing device for weighing the amount of cement to be supplied to the mixing device. The load or loads may be read and compared to a predetermined value.

Water and liquid composition may be added to the mixing device and then the cement may be added. Alternatively, water and cement may be added to the mixing device and then the liquid composition may be added.

The present disclosure further provides a rig comprising a grouting system 171 as disclosed herein.

The rig may be an equipment intended for earth surface use or underground use. The rig may be a mining or construction work machine adapted for various mining operations or construction work. The rig may be adapted for rock reinforcement, for example rock bolting.

The present disclosure further provides a computer-implemented method for determining a weight of a liquid composition using the dosing pump 101 as disclosed herein. The method is illustrated in a flow chart shown in figure 7 and comprises the actions listed below. Optional actions are marked by dashed lines.

Action S2: in a processor device 160 of a control system 159, receiving weight data from a load cell 151 configured to measure a weight of the dosing pump 101, the weight data being indicative of the weight of the dosing pump 101 while the liquid composition is being delivered to the first cylinder compartment 102, and Action S3: in the processor device 160, determining the weight of the liquid composition based on the received weight data.

The method may comprise:

- Action S1 : in the processor device 160, receiving weight data from the load cell 151 , the weight data being indicative of a weight of the dosing pump 101 without the liquid composition present in the first cylinder compartment 102, wherein determination of the weight of the dosing pump 101 is determined in the processor device 160 based on the received weight data, and in the processor device 160, receiving weight data from the load cell 151, the weight data being indicative of a weigh of the dosing pump 101 comprising the liquid composition, wherein the weight of the dosing pump 101 comprising the liquid composition is determined in the processor device 160 based on the received weight data.

The weight of the dosing pump 101 without the liquid composition may be subtracted from the weight of the dosing pump 101 comprising the liquid composition.

Further, the present disclosure provides a computer program product comprising instructions which, when executed on a processor device 160, cause the processor device to carry out the method as disclosed herein.

It is to be understood that the present disclosure is not limited to the embodiments described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the appended claims.

Claims

1. A dosing pump (101) for dosing a liquid composition, the dosing pump comprising at least a first and a second cylinder compartment (102, 121) fluidly separated from one another, a first piston (103), a second piston (122), a first piston rod portion (104), and a second piston rod portion (123), the first cylinder compartment (102) being configured for filling and dosing the liquid composition, the first piston (103) being arranged in the first cylinder compartment (102), the second piston (122) being arranged in the second cylinder compartment (121) between the first piston rod portion (104) and the second piston rod portion (123), the first piston rod portion (104) mechanically connecting the first piston (103) to the second piston (122), whereby the first and second pistons (103, 122) are arranged for common movement along an axial direction Z, the first cylinder compartment (102) comprising an inlet (105) and an outlet (106) for the liquid composition and an opening (107) for air breathing, the first piston (103) being arranged to induce a flow of the liquid composition to/from the first cylinder compartment (102) via the inlet (105) and the outlet (106), respectively, the second cylinder compartment (121) being fluidly connectable to a hydraulic pump for hydraulically controlling the common movement of the first and second pistons (103, 122) along the axial direction Z, the first piston rod portion (104) and the second piston rod portion (123) having the same cross-sectional area, and a total length (L_tot) of the second piston (122) and the second piston rod portion (123) along the axial direction Z corresponding to at least a length (L) of the second cylinder compartment (121).

2. The dosing pump (101) according to claim 1 , wherein the first piston rod portion (104) extends through a first wall (110) separating the first cylinder compartment (102) from the second cylinder compartment (121), wherein the first wall (110) is arranged in a second cylinder compartment first end (127).

3. The dosing pump (101) according to claim 1 or claim 2, wherein the second piston rod portion (123) extends through a second wall (124) arranged in a second cylinder compartment second end (128).

4. The dosing pump (101) according to any of the preceding claims, wherein the second cylinder compartment (121) comprises a first port (125) and a second port (126) that are configured to be connected to a hydraulic pump.

5. The dosing pump (101) according to any of the preceding claims, wherein the first port (125) is arranged at a second cylinder compartment first end (127), and the second port (126) is arranged at a second cylinder compartment second end (128).

6. The dosing pump (101) according to claim 5, wherein each one of the ports (125, 126) is configured to alternatively receive hydraulic fluid and alternatively dispatch hydraulic fluid.

7. The dosing pump (101) according to any of the preceding claims, wherein the dosing pump (101) comprises a load cell (151) configured to measure a weight of the dosing pump (101).

8. The dosing pump (101) according to any of the preceding claims, wherein the dosing pump (101) comprises a third cylinder compartment (141) arranged for protecting the second piston rod portion (123).

9. The dosing pump (101) according to any of the preceding claims, wherein the dosing pump (101) is a dosing pump (101) for grouting.

10. A grouting system (171) configured to inject a grouting mixture comprising a liquid composition into a bore hole (181), the grouting system comprising at least one dosing pump (101) according to any of the preceding claims for dosing the liquid composition.

11. A rig comprising the grouting system (171) according to claim 10.

12. A computer-implemented method for determining a weight of a liquid composition using the dosing pump (101) according to any of claims 1-9, wherein the method comprises: in a processor device (160) of a control system (159), receiving (S2) weight data from a load cell (151) configured to measure a weight of the dosing pump

(101), the weight data being indicative of the weight of the dosing pump (101) while the liquid composition is being delivered to the first cylinder compartment

(102), and in the processor device (160), determining (S3) the weight of the liquid composition based on the received weight data.

13. The computer-implemented method according to claim 12, wherein the method comprises: in the processor device (160), receiving (S1) weight data from the load cell (151), the weight data being indicative of a weight of the dosing pump (101) without the liquid composition present in the first cylinder compartment (102), wherein determination of the weight of the dosing pump (101) is determined in the processor device (160) based on the received weight data, and in the processor device, receiving weight data from the load cell, the weight data being indicative of a weight of the dosing pump (101) comprising the liquid composition, wherein the weight of the dosing pump (101) comprising the liquid composition is determined in the processor device (160) based on the received weight data, and

- wherein the weight of the dosing pump (101) without the liquid composition is subtracted from the weight of the dosing pump (101) comprising the liquid composition.

14. A computer program product comprising instructions which, when executed on a processor device (160), cause the processor device (160) to carry out the method according to any of claims 12 or 13.