US3424438A

US3424438A - Bulk storage,transport,mixing and delivery apparatus

Info

Publication number: US3424438A
Application number: US673389A
Authority: US
Inventors: George F Knotts; Herbert K Beyer
Original assignee: AmerInd Inc
Current assignee: AmerInd Inc
Priority date: 1967-10-06
Filing date: 1967-10-06
Publication date: 1969-01-28
Anticipated expiration: 1986-01-28

Description

BULK STORAGE, TRANSPORT, MIXING AND DELIVERY APPARATUS Filed OCT.. 6. 1967 Jan. 11M; 1969 G. F. KNoTTs ET AL Sheet 1 of 3 FIGI.

FICE.

|NvENToRs; GEORGE F. KNOTTS HERBERT K. BEYER ATT YS.

Jan. 28, 1969 G, F, KNO-ns ET A1. 3,424,438

BULK STORAGE, TRANSPORT, MIXING AND DELIVERY APPARATUS Filed Oct. 6, 1967 Sheet 2 of 5 FGB. :in

GEORGE F. KNOTTS HERBERT K. BEYER ATTYS,

INVENTORSI Jan. lwf (3l F, KNOTTS ET AL. 3,424,438

BULK STORAGE, TRANSPORT, IXING AND DELIVERY APPARATUS Filed Oct. 6, 1967 Sheet 3 of 5 HERBERT K. BEYER @9 wvl-:moms: 59@ m GEORGE F. ANOTTS ATTYS 3,424,438 Patented Jan. 28, 1969 11 Claims ABSTRACT F THE DISCLUSURE Bulk transport, storage, mixing, and delivery apparatus which includes a truck having a storage tank mounted thereon for carrying ammonium nitrate prills and at least one other storage tank for carrying fuel oil to a blast area. The apparatus is adapted to mix predetermined quantities of the ammonium nitrate prills and oil at the blast area and discharge the same into, for example, -bored holes (blow holes) for detonation. At the lower portion of the ammonium nitrate prill tank is a feed conveyor which moves the ammonium nitrate prills out of the tank into an air lock which is geared for rotation with the screw type conveyor. A second feed conveyor in the form of a positive displacement `fuel oil -pump is positioned to draw a suction from the fuel oil tank and deliver the fuel oil into a mixing chamber, into which the air lock opens. The mixing chamber is in turn connected to a pneumatic discharge line for carrying the mixture directly into the bored shot hole. The rfuel oil pump and the screw type conveyor are connected together for simultaneous operation, both being operated from and actuated by a hydraulic drive system having a single control which permits accurately predetermined mixes to be carried by the discharge conduit into the bored hole.

that the ammonium nitrate prills and the fuel oil be transported to the blasting site in separate containers and there mixed and delivered into the blow holes for detonation. The `mixing of the ammonium nitrate prills with the fuel oil presents difficulties because of the decreased sensitivity and effectiveness of the mixture if the percentage by weight of the fuel oil varies more than the normal allowed tolerance of approximately 5.7-6.2%, For example, variations in the fuel oil of as little as 2% by weight will deleteriously affect the efficiency of the detonation.

Numerous vehicular transports of various designs have been used in order to effect the desired end of carrying the ammonium nitrate and fuel oil separately and mixing the same just prior to placing the mixture into a blow hole. The most common problem with the vehicular transports of the prior art has been the complexity of the systems used to control the metering of exact portions of the individual components to obtain the desired mixture. For example in vehicular transports presently in use, the fuel oil pump is not synchronously driven relative to the prill feed conveyor requiring continual adjustment of the pump output pressure in order to maintain the correct ammonium nitrate to fuel oil ratio. Secondly, although in vehicular transports of prior art design it is possible to `feed the fuel oil into a mixing chamber adjacent or in the discharge for lling the blow hole, it is difficult to mix the ammonium nitrate prills with the fuel oil in the mixing chamber without pressurizing the prill storage chamber because of packpressure in the mixing chamber which would tend to move the fuel oil into the prill storage tank, absent the pressure thereon.

To this end, it is a principal object of the present invention to provide a transportable storage, mixing, and delivery apparatus wherein an explosive may be mixed at the site and delivered into bore holes.

Another object of the present invention is to provi-de a nonpressurized storage and delivery system for ammonium nitrate prills `while providing means yfor feeding predetermined quantities of the prills to a mixing chamber for mixing the prills with `fuel oil to provide an explosive mixture.

Still another object of the present invention is to provide apparatus, in a vehicular explosive transport, for mixing the components of the explosive mixture at the blasting site and maintaining the explosive mixture at a predetermined percentage by Weight of the various components of the mix.

Yet another object of the present invention is to provide simplified control of the various apparatus in order that the mix ejected from the transporting apparatus is controllable by a single control, not requiring auxiliary adjustments of any kind.

Another object of the present invention is to provide pneumatic discharge apparatus for quick and convenient injection of the explosive mix into bore holes.

Still another object of the present invention is to provide a simple and unique pneumatic isolation means intermediate the mixing chamber and the prill storage discharge outlet [whereby backup of the prills into the prill storage tank is prevented.

Other objects and a `fuller understanding of the invention may be had by referring to the `following specication and claims taken in conjunction with the accompanying drawings in which:

FIG. 1 is a fragmentary schematic side elevational view illustrating portions of the apparatus of the present invention in section;

FIG. Z is an enlarged sectional view taken along line 2 2 of FIG. l;

FIG. 3 is an enlarged end elevational view as the apparatus appears from the right as viewed in FIG. l, and with portions of the apparatus removed;

FIG. 4 is an enlarged fragmentary sectional view taken along line 4-4 of FIG. 1;

FIG. 5 is an enlarged fragmentary sectional View taken along line S-S of FIG. 3;

FIG. 6 is a fragmentary sectional view taken along line 6 6 of FIG. 5, and as if FIG. 5 were not in section;

FIG. 7 is an enlarged fragmentary sectional View of a portion of the apparatus shown in FIG. l, and illustrating air discharge bypass means;

FIG. 8 is a schematic piping diagram showing the fuel oil supply and storage system of the present invention;

FIG. 9 is a schematic diagram of the main drive and control system of the apparatus of the present invention; and

FIG. 10 is a schematic representation of a modified main drive system.

Referring now to the drawings, and particularly FIG. 1 thereof, a transportable storage, mixing and delivery apparatus 10 is illustrated therein. As shown, the apparatus 10 includes a conventional truck 11 having a cab 12 and engine compartment 13 mounting a rearwardly extending frame 14, the truck being capable of movement as by wheels 15.

In order to provide an explosive mixture at and into, for example, a bore hole at a blast site, the apparatus includes four separate systems which may be classified as follows: a lirst material `storage and feed apparatus 20, for carrying, in the illustrated instance, ammonium nitrate prills; a second material storage and feed apparatus 40, for carrying, in the illustrated instance, fuel oil; an explosive mixture discharge apparatus 60 for delivering the mixture into, for example, bored blow holes at the blast site; and a main drive control system 80 for effecting positive control of the component materials into the mixture discharge apparatus 60.

Referring first to the first material storage and feed apparatus 20, this apparatus comprises a storage tank 21 mounted on the frame 14 of the truck 11 as by 4braces 16 (See FIGS. 1 and 2) and having an inlet for loading the tanks at the upper portion thereof, in the present instance there being three inlets designated 22a, 22b, and 22C. As vshown in FIG. 1, in the event that it is desirable to provide different materials for mixing, the tank 21 is compartmentalized as by partitions 23 which depend from the upper surface 21a of the tank 21, dividing the tank 21 into the number of compartments corresponding to the number of inlets.

As shown best in FIGS. 2-4, the storage tank 21 includes inwardly sloping bottom walls 24 which merge into an axially extending arcuate bottom portion 24a housing a first material conveyor means 25 therein. In the present instance and preferably the first conveyor means 25 comprises a screw or auger 26 which serves, upon actuation, to feed the material towards an outlet 27 (see FIG. 5) communicating with the lower portion of the storage tank 21. The auger 26, as may be seen in FIGS. 1, 4 and 5, includes a shaft 28 suitably journalled as at 29 at the opposite upstanding end walls 30a, 30h of the tank, for rotation of the auger.

As shown, the auger 26 extends the axial length of the tank 21, and in order that only a predetermined and finite amount of material is passed into the auger for feeding lof the ammonium nitrate prills towards the outlet 27, a metering shield 31 is superposed of the auger and extends axially the full length of the tank 21. As shown best in FIG. 4, the metering shield 31, along its extended terminal edges 31a, forms metering slots 32 with the inwardly sloping bottom walls 24. In this manner, the metering shield 31 cooperates with the auger to pass predetermined quantities of the material contained in the storage tank 21 to the outlet 27, which predetermined quantity becomes a function of the metering Islot Width, auger pitch and rotational speed.

After the material passes through the outlet 27 it is fed into a mixing chamber 38 where it is mixed with the liquid material such as fuel oil, and then discharged under pressure through suitable hose or the like into the blow hole. To this end, for reasons which will become more evident hereinafter, isolation means, in the present instance a rotary air lock 33 is interposed between the outlet 27 of the tank 21 and the mixing chamber 38. As illustrated in FIGS. 5 and 6, the air lock 33 includes a shaft 34 suitably journalled as at 35 at opposite sides of a housing 27a mounted adjacent the outlet 27. Radially projecting from the shaft 34 are a plurality of vanes 36 which extend axially of the shaft and er1- gage a cylindrical portion 27b of the housing 27a in rubbing engagement upon rotation of the shaft 34, thus dividing the portion 27b of the housing into a plurality of axially extending wedge-shaped compartments 36a. As shown in FIG. 5, a gear 34a pinned to the shaft 34, effects rotation of the vanes 36 due to the meshing of the gear 34a with a like gear 28a mounted on the shaft 28. Thus the material moving out the outlet 27 due to the action of the auger 26 drops into one of the compartments 36a, and upon continued rotation of the vanes due to the rotation of the shaft 28 of the auger 26, material in the compartments 36a is dumped into the mixing chamber 38. In this manner, and as will become more evident hereinafter, overpressure in the mixing chamber 38 will not be communicated into the outlet 27 of the tank 21 due to the isolation effect of the air lock 33 by the vanes 36.

In order to prevent the vanes 36 from making metal to metal contact with the cylindrical portion 27b of the housing 27a, the extended terminus of each vane is covered With a nonsparking substance 36b such as a polymerized iiuorocarbon resin, having low coefficients of friction to reduce the power required to rotate the vanes 36. Typical fluorocarbon resins which may be used in this connection are polytetrafluoroethylene sold by E. I. du Pont Co. under the trade name Teflon, or Kel-F, a polytriuorochloroethylene material sold commercially by M. W. Kellog Co.

As heretofore set forth, the `second material, for example fuel oil, is fed into the mixing chamber 38 for mixing with the first material, such as ammonium nitrate prills, f-or discharge into the bore hole. To this end, the second material storage and feed apparatus 40 is shown schematically in FIG. 8, the relative position of the various parts of the system Ibeing best illustrated in FIGS. 2, 3, and 6. As shown in FIG. 2, the apparatus 40 includes a pair of fuel oil storage tanks 41 having elevated or raised inlet and ventilation tubes 42 connected thereto. Suction is taken on the tanks 41 by a second material conveyor means, in the present instance and preferably a positive displacement fuel oil pump 45 which, through a `suction line 44 and strainer 44a is connected to a common suction line 43 connected through a valve 43a to the tanks 41. Thus, as desired, suction may be taken from one or both of the tanks merely by opening or closing the valve 43a. Interconnecting the tanks 41, at one end thereof, is a fill line 42a having a valve 43b therein. By opening the valve 43h, both tanks may be filled simultaneously.

As heretofore set forth, the pump should be of the positive displacement variety such as the Series 5200 fuel oil pump made by Hypro, Inc. of Minneapolis, Minn. This requirement of positive displacement is necessary in order to insure that an exact quantity of fuel oil will be supplied to the mixing chamber 38.

For reasons which will become more evident hereinafter, the pump 45 is preferably positioned for driving and thus pumping with at least its driven member positioned intermediate the back end of the cab 12 and the forward end wall 30a of the storage tank 21.

Output from the positive displacement pump 45 passes through the feed line 46, a meter guard valve 46a and a flow meter 46b. The meter may be of the type 31180 made by Bennett Industries, Inc. of Peotone, Ill. A pressure gauge 46c is located downstream of the meter and this gauge will give early indications of any malfunctions in the system, such as a clogged strainer, a dry tank, or dirt, etc. in the line. The fuel oil then passes through a second guard valve 47 and branch lines 47a, 47b into injection spray nozzles 48 which are positioned on opposite sides of the mixing chamber 38 for injecting `a spray of fuel oil into the mixing chamber for intimate contact with the ammonium nitrate prills (see FIG. 6). The spray nozzles are of a conventional type such as the diaphragm T-jet #8355 made by Spraying Systems Co. of Bellwood, Ill.

As the pump 45 is of the positive displacement type, it is preferable that a pressure relief valve be positioned in the line 46 so that in the event that one of the

valves

46a or 47 is shut olf, fuel oil may flow from the pump back into one of the storage tanks 41. Such a pressure relief valve is shown at 49 in FIGS. 2 and 8, the line 50 acting as a return into one of the tanks 41. In addition, a manual bypass line 51 having a guard valve 52 therein is also provided between the output side of the pump 45 and one of the tanks 41.

In the instance of fuel oil and ammonium nitrate 'as the explosive mixture, after the mixture has been formed in the mixing chamber 38, and simultaneously therewith, the mixture must be discharged for delivery into a blow hole. To this end the explosive mixture discharge apparatus 60 generally includes a pneumatic or air discharge system connected to the mixing chamber 38 for pneumatically discharging the mixture through outlet piping connected to the outlet side of the -mixing chamber for delivering the mixture into a blow hole or the like. As shown best in FIGS. l, 2, 5, and 7, the mixture discharge apparatus 60 comprises a blower 61 which is connected, via a conventional power take-off shaft 62 extending from the transmission 63 of the vehicle, to a power takeoff gear box 64. The blower may be of conventional centrifugal design such as the Sutorbilt 5 MVC or 6 MVB if a higher capacity is desired, made by Fuller Co. of Compton, Calif. As shown, the blower 61 takes air suction through the upstanding suction piping 65 positioned adjacent the end wall 38a of the storage tank 21. As shown in FIG. 1, the blower 61 may be 4mounted on a platform 66 connected to the frame 14 of the track 11. Connected to the discharge side of the blower 61 is air discharge conduit 67 which is connected to and integral with the inlet end 38a of the mixing chamber 38.

At the outlet 38b of the mixing chamber 38 is a short length of pipe 68 to which is connected suitable closure means such as a cap 69 and to which, upon removal of the cap, high pressure hose 78, conveniently mounted in a rack 71 along the side walls of the storage tank 2l. may be quickly connected for discharging the mixture into a blow hole.

As it is easier to hook-up the hose 70 to the pipe 68 without air passing through the pipe, air bypass means are provided in the conduit 67 to redirect the air as desired. To this end, and `as best shown in FIGS. 1 and 7, the air bypass means comprises an aperture 72 in the side wall of the conduit 67, and includes a bypass damper valve 73 pivotably mounted as at 74 for closing off the flow of air through the conduit 67 `and to the mixing chamber 38 while permitting the air flow to be bypassed through the aperture 72 into stub piping 74a. The damper valve may be operated by any convenient means such as a handle (not shown) projecting through the side wall of the conduit 67, which handle may be weighted to keep the damper valve in a position normally closing olf the aperture 72.

As heretofore set forth, when mixing fuel oil and arnmonium nitrate together to form an explosive, it is desirable to maintain the mixture, as closely as possible, to 94% ammonium nitrate and 6% by weight of fuel oil. The accuracy of the quantities of fuel oil and ammonium nitrate prills in the mixing chamber is directly related to the rotational velocity of the auger 26 and the speed, relative to displacement, of the fuel oil pump 45. Thus, once the desired parameters are known, the auger and fuel oil pump may be driven simultaneously from common drive means, and the operator, in order to start and stop the system merely has to control the actuation and de-actuation of the drive means.

To this end, and as best shown in FIG. 2, the shaft 28 of the auger 26 projects through the end wall 30a of the storage tank 21 and is connected directly to a rst drive sprocket 75 which, via chain 75a is connected to drive means having a sprocket 89a mounted thereon. As shown in FIGS. 1 and 2, a second sprocket 76, connected to the shaft 28 for rotation therewith, is connected through a chain 76a to a sprocket 77 mounted on the drive shaft 78 of the fuel oil pump 45. Thus as the drive means causes rotation of the sprocket 75, the fuel oil pump 45 is driven simultaneously so that feed of the ammonium nitrate and fuel oil is simultaneous.

For ease of control, smoothness of operation, and primarily for safety, a hydraulic driven means is incorporated as part of the control system 80 for effecting positive -control of the feed of the mixture into the mixture discharge apparatus 60. To this end, and `as best illustrated in FIGS. 1, 2, and 9, a hydraulic pump 81 is connected via suitable gearing to the power take-olf gear box 64, the pump being connected through suitable suction piping 82 to a pump 83. The pump discharges through suitable piping 84 into a pressure regulator valve 85 which serves, when pressure builds up in the system above a certain predetermined level, in the present instance approximately 1500 p.s.i., to cause hydraulic fluid flow through the bypass line 84a into the sump 83. As shown in FIGS. 1 and 9, a preferably non-'metering actuator valve 87 is positioned at the rear of the truck and is connected, by piping 86, to the pressure regulator valve and to the drive means. In the present instance the drive means includes a hydraulic motor 89 which is connected to the actuator valve 87 by piping 88. A return line 90 extends from the hydraulic motor 89, in a conventional manner, to the sump 83. Thus to energize both the auger and fuel oil pump to provide a flow of ammonium nitrate and fuel oil to the mixing chamber 38 requires actuation of the actuator valve 87, while in order to shut-off the flow of the system merely requires closing olf of the valve 87 thus preventing further flow of hydraulic fluid to the hydraulic motor 89. The drive and control system may be composed of easily purchased parts, for example the pump 81 may be purchased from Gresen Mfg. Co. of Minneapolis, Minn., Model #li-7; the motor may be purchased from Energy Conversion Systems Corporation of Grafton, Wis., Model #tt-802 (10 H.P.); and the pressure regulator 85 may be purchased from Double A Products Co. of Manchester, Mich., Model #BT-06- 211-10A2.

In certain situations where a plurality of bore holes must be filled with the explosive mixture at the blasting site, which holes may be of varying depth and/ or different diameters, it may be desirable to vary the rate of discharge of the explosive mixture into the bore holes. If variations in ow are desirable, it is possible to vary the speed of the auger `and fuel pump so as to increase or decrease the mixture output. To this end a transmission 92 may be incorporated intermediate the hydraulic drive motor 89 and the sprocket 89a (see FIG. 10). Such a transmission as the Chelsea Manufacturing Company Model #2658 three-speed transmission, may be used to vary the output of the mixture between .approximately and 500 pounds per minute, without adversely affecting the delivery of the fuel oil pump.

Thus the apparatus of the present invention provides a relatively simple bulk transport, storage, mixing, and delivery apparatus which is extremely simple to control and does not require individual control of the constituents of the mix. In addition, by the positive action of the feed of the present invention, accurate quantities of ammonium nitrate and fuel oil are provided at the mixing chamber for discharge by the discharge system.

Thus although the invention has been described with a certain degree of particularity, it should `be understood that the present disclosure is only exemplary of the invention, and that numerous changes in the details of construction, and the combination and arrangement of parts may be made without departing from the spirit and scope of the invention as hereinafter claimed.

What is claimed is:

1. A storage, mixing, and mixture delivery apparatus comprising in combination: a first storage tank having a rst material conveyor means extending axially of the tank and mounted at the lower portion thereof, said tank having an inlet and outlet, said outlet being in communication with said conveyor; at least a second material feed tank, and second material conveyor means connected thereto; pneumatic discharge means and means to provide air to said discharge means; drive means operatively connected to said rst and second material conveyors to impart, upon actuation thereof, simultaneous movement to said conveyors; a mixing chamber connected to said pneumatic discharge means and in communication therewith,

said mixing chamber being connected to and in communication with the outlet of said rst material storage tank and to the output of said second material conveyor means; and isolation means intermediate said rst storage tank outlet and said mixing chamber and operable to prevent pneumatic pressure from said pneumatic discharge from owing into said outlet of said rst storage tank while permitting material to ow from said first tank into said mixing chamber.

2. Apparatus in accordance with claim 1 wherein said first storage tank includes inwardly sloping bottom walls merging into an axially extending arcuate bottom portion, said rst conveyor means comprising an auger mounted for rotation in said arcuate bottom portion.

3. Apparatus in accordance with claim 2 including a metering shield overlying said auger, said metering shield having axially extending terminal edges inwardly spaced from said .bottom walls whereby material may be metered through the slots formed between the terminal edges and said bottom walls.

4. Apparatus in accordance with claim 1 wherein said isolation means comprises a rotary air lock including a housing connected to and adjacent said outlet of said first storage tank, a shar't extending axially of said housing and a plurality of radially projecting vanes extending axially of said shaft and engaging said housing in rubbing contact whereby said housing is divided into a plurality of axially extending wedge-shaped compartments, and means to eifect rotation of said vanes.

5. Apparatus in accordance with claim 4 wherein each of the portions of said vanes in rubbing engagement with said wall of said housing is covered with a low friction, non-sparking substance.

6. Apparatus in accordance with claim 5 wherein said substance comprises a polymerized iluorocarbon resin.

7. Apparatus in accordance with claim 1 wherein said second material feed tank and said second material conveyor are adapted to store and feed, respectively, a liquid; said second material conveyor means including Ia positive displacement pump whereby an exact quantity of liquid material may be supplied from said pump to said mixing chamber.

8. Apparatus in accordance with claim 7 including injection spray nozzles positioned on opposite sides of said mixing chamber and in communication therewith for injecting a spray of liquid material into said mixing chamber.

9. Apparatus in accordance with claim 1 wherein said pneumatic discharge means includes a blower, a conduit leading from said blower connected to said mixing chamber and in communication therewith, air bypass means in said conduit to discharge said air externally of said conduit and to impede the flow thereof through said mixing chamber as desired.

10. Apparatus in accordance with claim 1 wherein said drive means includes a hydraulic motor operatively connected to control means, hydraulic pump means land means to actuate said pump, said pump connected to said hydraulic motor through said control means, and a sump and pressure regulated dump valve connected to the discharge side of said pump to effect dumping of hydraulic pressure from the discharge side of said pump into said sump at a predetermined pressure level.

11. Apparatus in accordance with claim 1t) including a transmission intermediate said pump and said rst and second material conveyors.

References Cited UNITED STATES PATENTS 2,094,839 10/1937 Gassman et al. 259-151 XR 2,161,553 6/1939 Westberg et al. 259-151 3,310,293 3/1967 Zimmerman 259-151 WALTER A. SCHEEL, Primary Examiner.

JOHN M. BELL, Assistant Examiner.

U.S. C1. X.R.