US3354771A - Apparatus for the charging of blast holes - Google Patents

Description

Nov. 28, 1967 s. A. J. STARK 3,354,771

APPARATUS FOR THE CHARGING OF BLAST HOLES Filed Aug. 17, 1965 3 M 43mm United States Patent 3,354,771 APPARATUS FOR THE CHARGING 0F BLAST HOLES Seymour A. J. Stark, 193 St. Georges Road, Observatory Extension, Johannesburg, Transvaal, Republic of South Africa Filed Aug. 17, 1965, Ser. No. 480,328 Claims priority, application Republic of South Africa, Aug. 25, 1964, 64/4,033; Sept. 24, 1964, 64/4,555; Feb. 4, 1965, 65/577 8 Claims. (Cl. 86-20) ABSTRACT OF THE DISCLOSURE The apparatus for charging blast holes is made up of two flexible conduit connected parts. The first part is stationary and consists of a hopper which discharges into a gate controlled charge measuring chamber. The chamber discharges into a venturi of an air pressure conveyor conduit controlled by a spring loaded valve assembly. The gate is controlled by a push rod of a pneumatic rolling diaphragm assembly the piston of which is spring loaded. The second part is transportable and includes a pair of air control valves operated manually through a pistol grip trigger assembly. Manual operation of the trigger and control valves opens the air pressure conveyor conduit valve and simultaneously operates the roller diaphragm assembly to close the gate into the measuring chamber.

This invention relates to apparatus for the charging of blast holes drilled in rock with granular type explosive. The apparatus is particularly suitable for use in underground mining operations.

Devices have been produced to enable measured quantities of granular ammonium nitrate to be introduced into blast holes drilled in rock. In general such devices cannot be easily moved from place to place and require more than one workman for this operation.

It is the object of this invention to provide apparatus whereby charging of blast holes in the manner referred to can be more easily and expeditiously effected than with presently available means.

In machines of the type above referred to it is also desirable to have a hopper holding a bulk supply of the explosive from which predetermined quantities may be automatically dispensed. Sliding gates have been tried for this purpose but have not been wholly satisfactory because of the difliculty of obtaining adequate clearances for operation of the gates while maintaining proper sealing against the pressurised system of pneumatic conveyance. Rigid hoppers to hold a sufficient quantity of the explosive are bulky, liable to damage and diflicult to handle in confined areas such as those encountered in underground mining operations.

It is a further object of this invention to provide apparatus for dispensing quantities of particulate or some fluid substances which will enable a hopper, not subject to the above disadvantage, to be used which will have adequate outlet control into a pressurised system.

According to this invention there is provided blast hole charging apparatus comprising a hopper with a gate in the base thereof and adapted to be connected into a compressed air supply line, a pneumatic rolling diaphragm and push rod assembly operatively connected to the gate and a control valve assembly for the air supply, and means for remotely controlling the operation of the diaphragm and push rod and the control valve.

Further features of this invention provide for the control of the piston to be effected through a secondary air supply line and a pair of manually operable valves operated in unison through a trigger mechanism.

This invention also provides for the gate to open into a metering chamber of variable capacity and for the gate to be in the form of a rotatable plug above a seal and in the form of part of a hollow sphere with axial pintles integral therewith, the seal being located around a discharge opening from the hopper.

Other features of this invention provide for the hopper to comprise downwardly directed conical base having a flexible bag secured around the upper part of the base and means for introducing material to be dispensed from the hopper into the bag and for the bag to be made from rubberised fabric with a firm rib around the mouth of the bag at one end and a hinged lid to the opposite end of the bag where bag and lid are also supported by firm ribs.

The preferred form of this invention will be described with reference to the accompanying partly sectional drawings in which:

FIG. 1 is an elevation of the normally stationary part of the apparatus, and

FIG. 2 is a similar view of the manually operable valves for the apparatus on a slightly larger scale.

In the embodiment shown all metal components which may come into contact with the granular explosive are made of corrosion resistant material.

The apparatus is made in two parts one of which is adapted to remain substantially stationary during use while the other consists of the control mechanism and is readily transportable.

The stationary section of the apparatus consists of a hopper 1 having a normally open gate 2 at the bottom thereof discharging into a chamber 3 of a size which will house the maximum amount of granular explosive required for charging a single blast hole.

Connected to this gate 2 is a pushrod 4 of a pneumatic rolling diaphram assembly 5, the piston of which is spring loaded to the retracted position in which position the gate 2 in the hopper 1 is maintained open. The gate 2 in FIG. 1 is shown in the closed position. The chamber 3 has an outlet connected through a venturi located at 6 to discharge into a length of flexible hose 7 the free end 8 of which passes through the control mechanism and terminates in a length of rigid tubing 9 which is adapted to be inserted in a blast hole.

The transportable part of the apparatus is supported on a pistol grip type mounting 10.

A trigger assembly 11 is associated with the piston grip 10 to operate in unison a pair of air control valves the inlet one 12 of which is normally closed and the outlet one 13 normally open. A pair of suitably protected small diameter bore flexible tubes 14, 15 lead from the piston grip mounting 10 back to the stationary part of the apparatus. One of the tubes 14 leading to the inlet control valve 12 is connected to the main air supply 16 through the valve assembly 17 on the stationary part and described more fully below and the other tube 15 to the rolling diaphram and push rod assembly 5.

In this manner operation of the trigger 11 will allow air to pass to move the pushrod 4 while the normal outlet 18 from the assembly 11 is closed by operation of the outlet control valve 13. When the trigger 11 is released the position of the control valves 12, 13 is reversed so that air can escape from the assembly 5 and the pushrod 4 Will retract under the influence of the spring loading. It will be noted that the outlet part 19 from the mounting 10 is located between the valves 12, 13 and forms the connection to the tube 15.

The valve assembly 17 includes a spring loaded valve arranged in such a manner that when the control valve 12 is closed the valve closes the passage of the main air 3 supply 16 to the tubing 20 which is in direct communication with the flexible discharge hose 7.

When valve 12 is opened, this causes the valve closing passage 20 to open as well so that there is a flow of main air through flexible discharge hose 7 and outlet tube 9 therefor.

The measuring chamber 3 will preferably be made in two telescoping parts 21, 22 with a seal 23 between the adjacent surfaces. The two parts 21, 22 will preferably be held in telescoping engagement by means of screwthreads 23a so that a fine degree of volumetric control over the measuring chamber 3 can be obtained.

The lower end of this chamber 3 is adapted for, or forms part of, a connection into a pipeline for pneumatic conveyance as described above.

The upper end of the chamber 3 is secured around the central discharge opening 24 in the downwardly directed conically shaped base 25 of the hopper 1 for containing a bulk supply of granular explosive. The discharge opening 24 has a seal 26 therein forming a seat for a closure plug made in the form of part of a hollow sphere having axial outwardly projecting pintles supported in the hopper base 25 and at least one of which projects outwardly from the base for connection through rightangled lever arm 27 to the piston rod 4 for rotating the plug between open and closed positions relative to the discharge opening 24. It will be appreciated that the part spherical plug forms the hopper outlet gate 2 referred to above.

The base 25 of the hopper 1 preferably has supporting legs 28 for the apparatu attached thereto.

The upper end 29 of the base has a peripheral recess (not shown) formed therein so that a flexible rubberized fabric bag 30 forming the hopper body may have the mouth 31 thereof secured, by means of a wire or other form of circumferential clip 32, in sealing engagement with the base 25 of the hopper 1.

The dimensions of the bag 30 are as. in this case, a diameter of about 18 inches and a height of about 22 inches and in any event such that the bag 38 will be selfsupporting when charged with particulate material.

The upper end 33 of the bag 30 has a peripherally stiffened lid 34 which is adapted to engage with co-operating stiffening ribs 35 around the upper end 33 of the bag 30 and the lid is preferably hinged as indicated at 35 to the bag and means provided for locking the lid 34 to the bag 30.

From the above it will be appreciated that when there is no charge in the hopper 1 the body thereof may be collapsed onto the base 25. When the granular explosive is placed in the bag the body will be raised thereby only sufiicient to accommodate the charge. Thus the hopper has a variable capacity to suit particular requirements. This is advantageous where the apparatus is used in confined spaces such as in underground mining operations.

In use it has been found that the form of gate 2 for the hopper discharge opening 24 provides a good seal between the hopper 1 and the pressurized conveying system in tubing 7 when in the closed position. The shape of the gate also enables it to be easily moved into the open position through a body of granular charge in the hopper l and this is a highly desirable feature. Also, when in the open position the gate 2 does not interfere unduly with the flow of explosive into the measuring chamber 3.

When used for blasting in mining the hopper l is charged with explosive and, since the gate 2 is normally open, a measured quantity is fed into the chamber 3. This quantity is predetermined by the prior setting of the two parts 21, 22.

The end of the delivery tube 9 is inserted into the blast hole to be charged and the trigger ll operated. This enables air to move the pushrod 4 in the assembly 5 causing the gate 2 to close in the hopper base 25 and sequentially results in opening of the valve assembly 17 to enable the main air to carry the explosive from the chamber 3 and pack it into the blast hole as required.

When the trigger 11 is released the valve assembly 17 closes automatically and the hopper gate 2 opens for a fresh charge to enter the chamber 3.

The machine is then ready for the charging of the next hole.

It will be appreciated from the above that only one operator is necessary who has complete control of the blast hole charging at the rock working face.

What i claim as new and desire to secure by Letters Patent is:

1. Blast hole charging apparatus comprising a hopper having a base and a gate in the base, said hopper adapted to be connected to discharge into a compressed air supply line, a pneumatic rolling diaphragm and pushrod assembly operatively connected to said gate to move the latter, a control valve assembly for the air supply, and means for remotely controlling the operation of the pushrod and the control valve, said gate comprising a rotatable plug in the form of part of a hollow sphere with axial pintles projecting therefrom and journaled in said base and a seal retained in said base and cooperating with said gate.

2. Blast hole charging apparatus comprising a hopper having a base and a gate in the base, said hopper adapted to be connected to discharge into a compressed air supply line, a pneumatic rolling diaphragm and pushrod assembly operatively connected to said gate to move the latter. a control valve assembly for the air supply, secondary air supply lines connected to the rolling diaphram and control valve assemblies, a pair of manually operable valves to control air in the secondary supply lines and a trigger mechanism to operate the manually operable valves in unison. a metering chamber of variable capacity interposed between said hopper gate and the connection into the compressed air supply line.

3. Blast hole charging apparatus comprising a hopper having a base and a gate in the base formed as a plug of part hollow spherical shape with axial pintles projecting therefrom and a seal in the base for the plug, a metering chamber of variable capacity positioned below the gate and having the opposite end adapted for connection into a compressed air supply line, a pneumatic rolling diaphragm and pushrod assembly operatively connected to said gate to move the latter, a control valve assembly for the air supply and means for remotely controlling the operation of the pushrod and the control valve.

4. Blast hole charging apparatus as claimed in claim: 3 including a lever connecting one of the plug pintles to the pushrod of the rolling diaphram assembly.

5. Blast hole charging equipment as claimed in claim 3 in which the metering chamber is made in two telescoping parts with screwthread engagement between these two parts.

6. Blast hole charging apparatus comprising a hopper having a downwardly directed conical base and a flexible bag with a mouth secured around the upper part of the base, means for introducing material to be dispensed from the hopper into the bag, a gate in the base formed as a plug of part hollow spherical shape with axial pintles projecting therefrom and a seal in the base for the plug, a metering chamber of variable capacity positioned below the gate and having the opposite end adapted for connection into a compressed air supply line, a pneumatic rolling diaphram and pushrod assembly operatively connected to said gate to move the latter, a control valve assembly for the air supply and means for remotely controlling the operation of the pushrod and the control valve.

7. Blast hole charging apparatus as claimed in claim 6 in which the bag is made from rubberized fabric with a firm rim around the mouth of the bag, a removable lidprovided at the other end of the bag and peripheral stiffening ribs for this end of the bag and the lid.

8. Blast hole charging apparatus comprising a hopper having a base and a gate in the base, said hopper adapted to be connected to discharge into a compressed air supply line, a pneumatic rolling diaphragm and pushrod as sembly operatively connected to said gate to move the latter, a control valve assembly for the air supply, secondary air supply lines connected to the rolling diaphragm and control valve assemblies, a pair of manually operable valves to control air in the secondary supply lines and a trigger mechanism to operate the manually operable valves in unison, said hopper consisting of a downwardly directed conical base with the gate at the part of the base and means whereby material to be dispensed from the hopper may be introduced therein.

References Cited UNITED STATES PATENTS 2,834,245 5/1958 Osborne 8620 3,125,925 3/1964 Ljungberg 86-20 3,227,093 1/1966 Taplin 103150 FOREIGN PATENTS 704,354 2/1965 Canada.

SAMUEL FEINBERG, Primary Examiner.

apex thereof, a flexible bag secured around the upper 15 P, A, SHANLEY, A si t t E mi

Claims (1)

1. BLAST HOLE CHARGING APPARATUS COMPRISING A HOPPER HAVING A BASE AND A GATE IN THE BASE, SAID HOPPER ADAPTED TO BE CONNECTED TO DISCHARGE INTO A COMPRESSED AIR SUPPLY LINE, A PNEUMATIC ROLLING DIAPHRAGM AND PUSHROD ASSEMBLY OPERATIVELY CONNECTED TO SAID GATE TO MOVE THE LATTER, A CONTROL VALVE ASSEMBLY FOR THE AIR SUPPLY, AND MEANS FOR REMOTELY CONTROLLING THE OPERATION OF THE PUSHROD AND THE CONTROL VALVE, SAID GATE COMPRISING A ROTATABLE PLUG IN THE FORM OF PART OF A HOLLOW SPHERE WITH AXIAL PINTLES PROJECTING THEREFROM AND JOURNALED IN SAID BASE AND A SEAL RETAINED IN SAID BASE AND COOPERATING WITH SAID GATE.

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