GB2113191A - Apparatus for manufacturing anchor element cartridges - Google Patents

Abstract

Apparatus for manufacturing anchor element cartridges by blending pressure sensitive liquid-containing capsule particles with non-pressure sensitive hydraulic cement powder particles and discharging them into an elongated tubular casing comprises respective hoppers (1) for the pressure sensitive particles and the non- pressure sensitive particles, means (2) for transporting the particles from each hopper into a common receptacle (3) in which the particles are mixed without causing rupture of a substantial portion of said pressure sensitive capsule particles, filling funnel means (4) for filling with the mixed particles a vertically elongated flexible tubular casing (5), and vibrating support means (7) for positioning and holding the tubular casing during filling, whereby to consistently produce a packed tubular casing having mixed particles of an effective uniformity of density for use in fastening an anchor element in a hole in a support structure. The liquid- containing capsule particles are preferably water-containing microcapsules. <IMAGE>

Description

SPECIFICATION Apparatus for manufacturing anchor element cartridges This invention relates to an apparatus for manufacturing anchor element cartridges by blending pressure sensitive liquid containing microcapsule particles with non-pressure sensitive hydraulic cement powder particles and then packaging the blended particles in an elongated tubular casing.

Description of the Prior Art Considerable effort has gone into developing means for anchoring roof bolts as part of an effort to prevent roof collapses in mines. Obviously, there are many other applications that require grouting of an anchor element in a hole of a support structure.

The common commercial anchor element cartridge in use today comprises reactive components of a resin and a catalyst with the components in separate compartments of an elongated tubular casing which are brought into contact with one another upon injecting a bolt, and stirring the composition by rotating the bolt, thereby forming a hardened resin which anchors the bolt into the base.

Since the ventilation is often a serious problem in mines, the fumes that are given off by the reaction of the reactive components of the resin can cause serious health hazards to those people who have to work in the mines. Also, drippings from the reacted resin cartridges can also cause skin problems to workers.

Therefore, efforts have been made to produce anchor element cartridges which would provide effective fastening for the anchor element in a hole of a support structure and not give off the harmful fumes. One such successful solution to this problem is disclosed in U.S. Patent No. 4,096,944, incorporated herein by reference, wherein an anchor element cartridge is described comprising watercontaining microcapsules which are pressure sensitive combined with non-pressure sensitive hydraulic cement powder. When an anchor element is injected into the elongated cartridge which is in an elongated bore hole in the roof of a mine, the pressure from the anchor element causes a reaction to take place between the hydraulic cement powder and the water which is released from the pressure sensitive microcapsules.These cartridges do an effective job of anchoring without the harmful fume problem of the resin cartridges.

However, one of the problems with the hydraulic cement cartridges is that the cost of manufacturing using the conventional manufacturing equipment used for the resin cartridges produce a cartridge which is as expensive as the conventional resin cartridge.

Efforts to solve this problem initially were not successful because in the attempt to mix and package the pressure sensitive microcapsules and the hydraulic cement powders some of the microcapsules would break, thereby causing premature hardening of the cartridges.

The present invention seeks to overcome the above discussed deficiencies of the prior art and accordingly provides an apparatus for manufacturing anchor element cartridges by blending pressure sensitive liquid-containing capsule particles with non-pressure sensitive hydraulic cement powder particles and discharging them into an elongated tubular casing, comprising a first hopper for said pressure sensitive particles, a second hopper for said nonpressure sensitive particles, means for conducting particles from the first and second hoppers into a common receptacle in which said particles are mixed without causing rupture of a substantial portion of said pressure sensitive particles, filling meansforfilling with said mixed particles a vertically elongated flexible tubular casing located at a filling position, means for positioning a tubular casing in the filling position relative to said filling means, and vibrating means for vibrating said tubular casing during the filling thereof to produce consistently a packed tubular casing containing mixed particles with an effective uniformity of density for use in fastening an anchor element in a hole in a support structure.

Water-containing microcapsules are the preferred capsule particles. The preferred vibrating means comprises a first funnel means for collecting the mixed particles and transferring them to the tubular casing along with the vibrations from the funnel means.

Desirably, the bottom of the funnel means is attached to the top of the tubular casing, and the bottom of the tubular casing rests on a support means, which support means is preferably a vibrating support means.

The apparatus of the subject invention provides means for producing anchor element cartridges at a much higher rate which thereby significantly reduces the cost of these cartridges.

Additionally, it has been found that a more uniformly packed cartridge is possible using the apparatus of this invention to produce anchor element cartridges of the type described.

Thus, by the apparatus of the subject invention, it is now possible to produce a high quality hydraulic cement type anchor element cartridge at a cost which is highly competitive with the cost for the competitive commercial resin type cartridges.

A better understanding of the invention will be had from the following detailed description of some embodiments, given with reference to the accompanying drawing, in which: Figure 1 is a schematic representation of an apparatus according to the invention; and Figures 2 and 3 are schematic representations of two further embodiments of this invention.

The pressure sensitive capsule particles contain liquid and the non-pressure sensitive particles contain hydraulic cement powder. These are the principle ingredients of the filler for the cartridge made by the apparatus of this invention.

Chemicals for accelerating hardening may be added in amounts generally not exceeding about 3% of the weight of the cement powder. The hydraulic cement powder must be of the type that will harden when contacted with water or a similar liquid. Suitable types of hydraulic cement include portland, pozzolan, gypsum plaster, magnesium oxychloride and magnesium oxysulfate. The cement is generally used without any filler such as sand in order to form a stronger, faster hardening material.

The capsules containing the liquid are preferably spherical in shape. However, they may be elongated, threadlike, etc. They comprise an outer shell of an insoluble, frangible material which is pressure sensitive and which contains a small amount of liquid. The capsules are preferably microcapsules varying in size from about 400 to about 5000 microns in diameter.

The most preferred diameter of such microcapsules is between about 1000 and about 1 700 microns. The capsules serve to keep the liquid separate from the cement powder until the capsules are broken by application of pressure.

The liquid used in the capsules is preferably water or other liquid that will react with hydraulic cement to form a hardened mass capable of fastening an anchor element in a hole of a support structure. Preferably, the hardened mass is such that would be suitable for roof bolts in mines such as coal mines.

Fig. 1 of this invention discloses an apparatus according to this invention comprising a double hopper arrangement 1 wherein one of the hoppers is for the pressure sensitive containing microcapsule particles and the other hopper is for the non-pressure sensitive hydraulic cement particles. The double hopper 1 comprises means for transporting the particles from each hopper into a common receptacle, in the form of a funnelshaped bottom of the hopper 2. The common receptacle means 3 is preferably in the form of a funnel and comprises means for mixing the particles without causing rupture of a substantial portion of the pressure sensitive liquid-containing particles. This means for mixing can be the inclined sides of the funnel or, preferably, rotating horizontal discs with each disc being located under the point where the different particles come to the common receptacle means 3.The mixing means can also be blasts of air or other gaseous material, or other such means. The mixed particles then drop into filling means 4, preferably in the form of a funnel, for filling a first vertically elongated flexible tubular casing 5. The apparatus also contains means for positioning the tubular casing 5 in filling position relative to the filling means 4. This means for positioning can also include a vibrating means for vibrating the tubular casing during the filling step to consistently produce a packed tubular casing having mixed particles of an effective uniformity of density for use in fastening an anchor element in a hole in a support structure.The means for positioning and vibrating means may include a movable support 6 to move the tubular casing into position in a vertically elongated rigid frame 7, which preferably is in the form of a rigid tube with a closed bottom 8. The.elongated tubular casing 5 also preferably has a closed bottom. This casing is preferably made of plastic film such as polyolefin which is inexpensive and easily ruptured by -insertion of the anchor element.

The bottom of the filling means 4 is preferably attached to the top of the tubular casing 5 and the bottom of the tubular casing 5 rests on a support means such as movable support 6 or the bottom 8 of the vertically elongated rigid frame 7.

The movable support means 6, when vibrating during the filling operation, then transfers its vibrations to the vertically elongated tubular casing during the filling operation to obtain the desired end product. This apparatus is thus able to produce a high-quality product very rapidly. It also lends itself well to automation, the use of multiple filling arrangements for the elongated casings.

Fig. 2 describes a preferred embodiment of the apparatus of this invention wherein a double hopper 11 comprising a hopper for the pressure sensitive particles and a separate hopper for the hydraulic cement particles positioned above a common receptacle means 12 comprising means for mixing the particles without causing rupture of a substantial portion of the pressure sensitive particles. The funnel-means 13 is inserted in the top of an elongated tubular casing 14 which in turn is positioned inside of vertically elongated rigid frame 15, preferably in the form of a solid tube, in such a fashion that the frame 15 makes contact with funnel 13. Movable support 16 provides means for moving elongated tubular casing 14, funnel 13 and rigid frame 15 into filling position under common receptacle means 1 2.

Preferably the movable support 1 6 is in the form of a circular table top such that as the support means 1 6 rotates about a central axis, the filling operation takes place on a continuous means.

Also, the movable support means 16 provides a means of agitation for the mixed particles as they are filling the elongated tubular casing 14. This allows very rapid, uniform filling of the casing 14 to take place. When the casing 14 is suitably filled, it is closed and removed from the rigid frame 1 5 and the funnel 1 3 to give a final filled cartridge 17.

Fig. 3 describes another preferrred embodiment of a portion of this invention wherein hopper 21 for the pressure-sensitive particles of this invention feed to auger means 22 which transfers the pressure-sensitive particles to rotating disc 26 directly below the end of the auger means. The rotating disc is located in the common receptacle means 25. Similarly, hopper 23 for the nonpressure sensitive hydraulic cement particles transmits these particles to auger means 24, which in turn transmits them to rotating disc 27 located in common receptacle means 25. The simultaneous operation of the two rotating discs produces very rapid and effective mixing of the particles prior to transfer to the common receptacle means 25.

Example Using the apparatus of Fig. 1, two parts by weight of the hydraulic cement particles (of the alpha-type gypsum cement having an average particle size of 0.074 mm or 0.0017 inches) are mixed with one part of water-containing microcapsules having an average water payload of 0.625 percent and an average diameter of 1700 microns and wherein the capsules are made according to the method.for mass producing capsules outlined in U.S. Patent No. 3,389,194, incorporated herein by reference. High-quality cartridges are produced according to this method at a production rate of twenty (two-foot equivalent length, 24 inches (609.6 mm) actual length, and 0.95 inches (24.13 mm) diameter) cartridges per minute with a dispensing accuracy of + 2 grams or 1.3 percent.This compares to the prior art Chub-style machine and independent vibrator system production rate of 8 cartridges per minute with a dispensing tolerance of + 7 grams or 4.7 percent.

A cement-enhancing silicone fluid having a viscosity of 350 cps, sold under the trade name Dow Corning 200 Fluid, lubricates the cement.

particles and gives greater compaction of the cement and water microcapsule mixture, as described in our co-pending patent application having the same prioritydate and entitled "Improved Grouting Composition and Method of Using Same". The amount of water microcapsules is reduced by about 8%. The two-foot equivalent length cartridge of additive-enhanced cement is 20.5 inches (502.7 mm) long which gives distinct advantages in reducing packaging costs (less plastic sleeve material and shorter boxes), lowering bolt installing costs (faster), and increasing bolting machine safety (a straight-push and no-turn installing).

The cartridges which contain the silicone additive have a set-up time of 1 5 seconds from the time that the capsules are broken by pressure until the grouting composition is significantly hardened. This compares to a set-up time of about 1 minute for resin-based cartridges and about 35 seconds for the inorganic cement cartridges described above, except without the silicone additive. In a typical coal mine this equates to an increase in coal production of 1 5 to 20 percent for the silicone additive cement cartiridge over the resin cartridge. This saving in time obviously means a significant increase in coal production with very little increase in cost of overheads. Thus, the profitability of a coal mine can be significantly improved using cartridges made with the apparatus of this invention.

When filling the tubular casing with the mixed ingredients using the apparatus of Figure 1, it is preferred to vibrate the casing at a rate such that little product separation takes place, the cartridges are firm and easily handled, and localized hardening is avoided. Also, it is important that the tubular casing has a soft bottom so that rupture of the water capsules is avoided during the filling and vibrating step. Higher percentages of silicone additive in the cement also slightly shortened the vibration time period. Excessive vibration during filling caused local hardening in the cartridge whereas, for example, this local hardening was eiiminated by vibrating the tubular casing during filling at 250 cycles per minute for 35 seconds while replacing the metal clip at the bottom of the casing with a heat seal to provide a softer bottom of the cartridge.

A preferred mixture for the cartridge in one series of tests was determined to contain 1.5 percent (by weight) silicone and 1.5 percent potassium sulfate (accelerator) mixed at 0.29 water microcapsule to cement weight ratio based upon the shortest hardening time when inserting the anchor element and the best workability of any mix tested.

Pull tests of roof bolts installed in coal mines roofs using cement-water microcapsule cartridges produced using the apparatus of Fig. 1 and in accordance with the teachings of this invention, showed that the hardened grout containing the silicone additive had greater pull strength compared to otherwise similar hardened grout which did not contain the silicone additive.

Claims (18)

1. An apparatus for manufacturing anchor element cartridges by blending pressure sensitive liquid-containing capsule particles with nonpressure sensitive hydraulic cement powder particles and discharging them into an elongated tubular casing, comprising a first hopper for said pressure sensitive particles, a second hopper for said non-pressure sensitive particles, means for conducting particles from the first and second hoppers into a common receptacle in which said particles are mixed without causing rupture of a substantial portion of said pressure sensitive particles, filling means for filling with said mixed particles a vertically elongated flexible tubular casing located at a filling position, means for positioning a tubular casing in the filling position relative to said filling means, and vibrating means for vibrating said tubular casing during the filling thereof to produce consistently a packed tubular casing containing mixed particles with an effective uniformity of density for use in fastening an anchor element in a hole in a support structure.

2. An apparatus as defined in claim 1 , wherein said vibrating means comprises a funnel means for collecting the mixed particles and transferring them to said tubular casing along with the vibrations from said funnel means and wherein said liquid-containing capsule particles are watercontaining microcapsules.

3. An apparatus as defined in claim 2, wherein the bottom of said funnel means is arranged for the top of said tubular casing to be attached thereto, and support means is provided for the bottom of said tubular casing to rest thereon.

4. An apparatus as defined in claim 3, wherein said vibrating means is arranged to vibrate said support means.

5. An apparatus as defined in claim 1, wherein said packed tubular casing does not have any overpacked portions which will result in significant hardening of the mixed particles solely upon storage of said packed casing.

6. An apparatus as defined in claim 3 or 4, comprising means for attaching a further flexible tubular casing to a second funnel means.

7. An apparatus as defined in claim 6, comprising means for removing the first funnel means and the casing filled thereby from the filling position when said tubular casing is sufficiently filled with mixed particles, and then moving said second funnel means and further tubular casing into the filling position.

8. An apparatus as defined in claim 3, 4, 6 or 7, wherein the support means comprises a vertically elongated rigid frame arranged to surround the tubular casing.

9. An apparatus as defined in claim 8, wherein said vertically elongated rigid frame is in the form of a rigid tube with a closed bottom end.

10. An apparatus as defined in any one of claims 1 to 9, wherein an air mixing means is provided for mixing the particles in said common receptacle.

11. An apparatus as defined in claim 10, wherein said air mixing means comprises two rotating disks.

12. An apparatus as defined in any one of claims 1 to 11, wherein said means for conducting said particles from said hoppers comprises a separate auger for discharging from each hopper.

13. An apparatus as defined in claim 12, wherein each auger can be adjusted precisely as to the amount of particles transported to said common receptacle, as well as the length of time that such particles are transported.

14. An apparatus as defined in any one of claims 1 to 13, wherein said means for vibrating said tubular casing comprises means for vibrating at low frequency followed by a short period of high frequency vibrations.

1 5. An apparatus for manufacturing anchor element cartridges by rapidly blending pressure sensitive liquid-containing microcapsule particles with non-pressure sensitive hydraulic cement powder particles and discharing them into an elongated tubular casing comprising a first hopper for said pressure sensitive particles, a second hopper for said non-pressure sensitive particles, auger means for transporting said particles from each said hopper into a common receptacle, a rotary disk means for mixing the particles in the common receptacle means, said disk means being located in a substantially horizontal plane in said common receptacle means with sufficient spacing from the end of said auger means such that uniform mixing of said particles will take place without causing rupture of said pressure sensitive particles, vibrating funnel means for collecting the mixed particles from said common receptacle means and filling an elongated tubular casing, rigid vertically elongated tubular means for enclosing the tubular casing and capable of vibrating said casing during the filling thereof to produce a substantially uniform density of mixed and packed particles in said tubular casing.

16. An apparatus as defined in claim 15, wherein said vibrating funnel means comprises a multiple arrangement of funnels to remove the mixed particles from said common receptacle means and to be attached to respective rigid tubes enclosing elongated tubular casings.

17. An apparatus as defined in claim 16, wherein said multiple funnel arrangement comprises up to 24 funnels each of which can be pre-attached to a respective rigid tube containing an elongated tubular casing, the funnels being rotated such that a new funnel is positioned under said common receptacle after the previous funnel and associated elongated tubular casing have been filled.

18. An apparatus as defined in claim 17, wherein said multiple arrangement of funnels is fed by an additional apparatus as defined in claim 15.

1 9. An apparatus for manufacturing anchor element cartridges substantially as herein described with reference to the accompanying drawing.