AU2005257699B2

AU2005257699B2 - Method and arrangement for automatic mixing of water and concrete for rock bolting

Info

Publication number: AU2005257699B2
Application number: AU2005257699A
Authority: AU
Inventors: Hans Gustavsson
Original assignee: Epiroc Rock Drills AB
Current assignee: Epiroc Rock Drills AB
Priority date: 2004-06-23
Filing date: 2005-05-20
Publication date: 2010-03-04
Anticipated expiration: 2025-05-20
Also published as: ATE470546T1; NO20070409L; CA2563383C; WO2006001743A1; NO331760B1; EP1758718B1; DE602005021783D1; EP1758718A1; SE0401616D0; SE526474C2; SE0401616L; CA2563383A1; AU2005257699A1

Abstract

Method and arrangement for automatic mixing of water and concrete for rock bolting including adding water and concrete to a mixing vessel (1), mixing the water and concrete, and transferring the water and concrete to a drill hole(2). Water amount and concrete amount for the mixture of water and concrete is calculated in a control unit (3), that the calculated water amount is added to the mixing vessel (1), that the in the reality added water amount is weighed (4), that the calculated concrete amount is corrected considering the in the reality added water amount to obtain a correct mixture of water and concrete, that concrete and water are mixed during a predetermined time, and in that the mixture of water and concrete is transferred to a drill hole (2).

Description

1 METHOD AND ARRANGEMENT FOR AUTOMATIC MIXING OF WATER AND CONCRETE FOR ROCK BOLTING The present invention relates to a method and an arrangement for automatic mixing of water and concrete for rock bolting. 5 In the mixing of water and concrete for rock bolting it is customary to add measured volumes of water and concrete to a mixing vessel. Thereafter concrete and water are mixed until the mixture seems ready. A disadvantage with this method is that you get an admixture of air, which means that the mixing proportion between water and concrete becomes uncertain. This leads to that the 10 fastening of the rock bolt in the rock may be somewhat uncertain, ie. more rock bolts may be needed for the reinforcement of the rock than would be needed if the mixture of water and concrete had a more secure mixing proportion between water and concrete. It is therefore desirable for the present invention to achieve an automatic 15 method and arrangement for mixing of water and concrete that guarantees an accurate mixing proportion between water and concrete without negative influence from air admixture. According to one aspect of the present invention there is provided a method for automatic mixing of water and concrete for rock bolting including: 20 calculating, in a control unit, an amount of water and an amount of concrete for a mixture of water and concrete; adding the calculated amount of water into a mixing vessel; weighing the mixing vessel to establish a real added amount of water; correcting the calculated amount of concrete considering the real added 25 amount of water to obtain a correct mixture of water and concrete; adding concrete to the mixing vessel; mixing concrete and water during a predetermined time; and transferring the mixture of water and concrete to a drill hole. According to another aspect of the present invention there is provided an 30 arrangement for automatic mixing of water and concrete for rock bolting including: means for adding water to a mixing vessel; means for adding concrete to the mixing vessel; a mixer for mixing the water and concrete in the mixing vessel; 2 means for transferring the water and concrete to a drill hole; a control unit for calculating an amount of water and an amount of concrete for the mixture of water and concrete, the control unit being adapted to control the means for adding water and the means for adding concrete, the control unit being 5 further adapted to control an adding of the calculated amount of water and thereafter control the weighing of the mixing vessel to establish a real added amount of water, and further adapted to correct the amount of concrete considering the real added amount of water to obtain a correct mixture of water and concrete; and to control the adding of the corrected amount of concrete to the 10 mixing vessel, and further adapted to control the mixing of concrete and water during a predetermined time; and control and means for transferring the prepared water and concrete mixture to a drill hole. An embodiment of the invention is described below with reference to 15 enclosed figure, which shows schematically an arrangement for automatic mixing of water and concrete according to the invention. The arrangement disclosed in the figure includes a mixing vessel 1 in which a mixing arrangement in the form of a mixer 13 is arranged. The mixer is run by a motor 15, which running is controlled by a control unit 3. For 20 determination of the amount of material in the mixing vessel 1, this is arranged for weighing with a scale 4. Water is added to the mixing vessel 1 from a water source 16 via a valve 11 and a pipe 17. Concrete is added to the mixing vessel 1 from a supply 18 via a feeder 12 and a pipe 19. The valve 11 and the feeder 12 are controlled by the control unit 3. 25 The arrangement shown on the figure works in the following way. First the operator sets the demanded weight ratio between concrete and water and the demanded total weight for the mixture unless the whole volume of the mixing vessel is demanded. These values are stored in the control unit 3. The control unit 3 then calculates the demanded weights of concrete and water from either 30 the demanded weight of the completed mixture or from the volume of the mixing vessel 1. The mixing starts by weighing the amounts of water and concrete with the scale 4. In the shown example the mixing vessel 1 is standing on the scale 4. The mixing vessel may of course be hung up, e.g. in a load cell. The water is 3 added quickly from the source 16 to about the wished amount. Thereafter, the amount of concrete is recalculated to take into account the real amount of water. The concrete is added to the mixing vessel 1 with the feeder 12, e.g. a screw feeder. Thereafter the motor 15 is started to run the mixer 13 a predetermined 5 time set in the control unit 3. When the mixing has been made, the mixture of water and concrete is transferred to the drill hole 2 with the pump 14. When the mixture of water and concrete has been transferred to the drill hole 2, the mixing vessel 1 and other equipment should be cleaned to prevent that the equipment is destroyed at an interruption of the work. This is made by 10 adding water to the mixing vessel 1 until the water level 5 reaches an upper, selectable limit. The mixer 13 and the pump 14 are run during the whole cleaning procedure. The water level 5 is determined with the help of the scale 4. When the water level 5 has reached a lower limit, then the mixing vessel is refilled to the upper level. This method is repeated a predetermined number of times or during 15 a predetermined time. When the cleaning is carried through the equipment is switched off and the mixing vessel 1 is emptied. The whole process is controlled by the control unit 3. An advantage with this method is that it is automatic so that the operator can leave the equipment and perform other work at the same time as the cleaning is performed.

Claims

1. Method for automatic mixing of water and concrete for rock bolting including: calculating, in a control unit, an amount of water and an amount of 5 concrete for a mixture of water and concrete; adding the calculated amount of water into a mixing vessel; weighing the mixing vessel to establish a real added amount of water; correcting the calculated amount of concrete considering the real added amount of water to obtain a correct mixture of water and concrete; 10 adding concrete to the mixing vessel; mixing concrete and water during a predetermined time; and transferring the mixture of water and concrete to a drill hole.

2. Method according to claim 1, further including: filling the mixing vessel with water, after transferring the water and 15 concrete mixture to the drill hole; controlling, by the control unit, the water level in the mixing vessel between an upper level and a lower level; and repeating the steps of this claim for a predetermined time or a predetermined number of times. 20

3. Arrangement for automatic mixing of water and concrete for rock bolting including: means for adding water to a mixing vessel; means for adding concrete to the mixing vessel; a mixer for mixing the water and concrete in the mixing vessel; 25 means for transferring the water and concrete to a drill hole; a control unit for calculating an amount of water and an amount of concrete for the mixture of water and concrete, the control unit being adapted to control the means for adding water and the means for adding concrete, the control unit being further adapted to control an adding of the calculated amount of water and 30 thereafter control the weighing of the mixing vessel to establish a real added 5 amount of water, and further adapted to correct the amount of concrete considering the real added amount of water to obtain a correct mixture of water and concrete; and to control the adding of the corrected amount of concrete to the mixing vessel, and further adapted to control the mixing of concrete and water 5 during a predetermined time; and control and means for transferring the prepared water and concrete mixture to a drill hole.

4. Arrangement according to claim 3, further including: means for filling of the mixing vessel with water after the transferring of the 10 water and concrete mixture to a drill hole; and means in the control unit for controlling the water level in the mixing vessel between an upper level and a lower level for a predetermined time or a predetermined number of times.

5. Method according to any one of the embodiments herein described with 15 reference to the accompanying figure.

6. Arrangement according to any one of the embodiments herein described with reference to the accompanying figure. ATLAS COPCO ROCK DRILLS AB WATERMARK PATENT & TRADE MARK ATTORNEYS P27709AU00