US3840186A

US3840186A - Unit for feeding difficult to feed materials

Info

Publication number: US3840186A
Application number: US00300180A
Authority: US
Inventors: J Broadfoot
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-10-24
Filing date: 1972-10-24
Publication date: 1974-10-08
Anticipated expiration: 1991-10-08
Also published as: AU6157473A; DE2353509C2; JPS5243314B2; FR2213216A1; GB1415556A; FR2213216B1; DE2353509A1; CA1003003A; JPS4994080A; CH576055A5; SE393557B; IT994793B; AU470688B2

Abstract

Difficult to feed materials, such as quick-set additives for wet or dry concrete, are fed into contact with the concrete in particular form. A compact mass of the material is advanced into contact with an abrasive means to erode away the material in particulate form from the compacted mass at a predetermined rate. The particulate material is then conveyed in a fluid medium into contact with wet or dry concrete. Dual side-by-side units are provided with means to separately actuate each unit to provide uninterrupted delivery of the particulate material to a use location.

Description

I Oct. 8, 1974 United States Patent [191 Broadfoot 1 1 UNIT FOR FEEDING DIFFICULT TO FEED MATERIALS Primary Examiner-Roy Lake Assistant Examiner-E. F. Desmond Attorney, Agent, or FirmSeed, Berry, Vernon & Baynham [22] Filed:

[57] ABSTRACT Difficult to feed materials, such as quick-set additives [21] Appl. No.: 300,180

for wet or dry concrete, are fed into contact with the [52] US. 241/15, 241/38, 241/101.6, concrete in particular form A compact mass of the material is advanced into contact with an abrasive means to erode away the material in particulate form from the compacted mass at a predetermined rate.

28 2 88 .8 22 2 N 682 M 2 B11 7 M Z "4 W A M5 "18 "3 1. n 4 m2 Mb. "6 r. m 1 m cm 9 hm.. 1: 8 55 1:1

The particulate material is then conveyed in a fluid References Cited medium into contact with wet or dry concrete. Dual UNITED STATES PATENTS side-by-side units are provided with means to separately actuate each unit to provide uninterrupted delivery of the particulate material to a use location.

241/38 X 241/282 241/282 8 Claims, 5 Drawing Figures 2,561,043 3,182,920 5/1965 Daniels. 3,688,997 9/1972 U11ner.......

PATENTEU 81374 3,840,186

SHEET 1 0f 3 FIGO 2 PATENHU BET 74 rm //1 fi SHEET 2 BF 3 UNIT FOR FEEDING DIFFICULT TO FEED MATERIALS BACKGROUND OF THE INVENTION used are expensive and difficult to accurately feed because of their tendency to cake, build up on sliding surfaces and adhere to the surfaces of the container holding the same. These additives are also dusty, extremely noxious and caustic to the extent that use of such additives has been forbidden by some states due to working condition regulations. Powdered additives of this type are commercially available and sold under the tradenames Tricosol by Chemische Fabrik Grunau, GmbH, Accelleset" by Protex Industries, Inc., Unicrete X by Sayder Manufacturing Company and Quickset by Master Builders. Tricosol, for exampie, is a blend of sodium carbonate and sodium aluminate in a weight ratio of about 2:1. Means are disclosed for metering a quick-setting additive into contact with wet or dry concrete in US. Pat. application Ser. No. 175,764, filed Aug. 27, 1971; however, the metering device disclosed has a feed rate which varies plus or minus percent or more. This results in inefficient wasteful use of the additive. In addition, if the additive is allowed to sit in the holding vessel of the metering device described in the application for a period of time or allowed to come into contact with a damp atmosphere, it sets to a hard, rock-like mass which is unworkable. It has thus remained a problem to devise means for accurately and uniformly feeding quick-set additives for wet or dry concrete.

SUMMARY OF THE INVENTION This invention relates to a method and means of accurately and uniformly feeding a hard to feed material, such as a quick-set additive for concrete as a particulate material wherein the material is first formed into a compacted mass and the mass advanced into contact with an abrading means which erodes away a portion of the material as a particulate material for conveyance by suspension in a flow of fluid medium to a use area.

The objects of this invention are to provide: (1) a process and apparatus for accurately and uniformly feeding a hard to feed material as a particulate material; (2) a process and apparatus for first forming a hard to feed material into a compacted mass and then advancing the mass into contact with abrading means which erodes away the material at a predetermined rate as particulate material for feeding by suspension in a fluid medium location; (3) to provide a process and apparatus for accurately and uniformly metering quickset additives for wet or dry concrete in a simplified and uncomplicated manner.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view of an overall system for 2 metering a quick-set additive for concrete in conjunction with a concrete pump;

FIG. 2 is a top view of the feed unit of this invention;

FIG. 3 is a cross-sectional view of the feed unit illustrating mounting of the abrading wheel and material feeding means;

FIG. 4 is a vertical cross-sectional view of the abrading wheel housing and abrading wheel therein along section line 4-4 of FIG. 3; and

FIG. 5 is a schematic of the control system for switching between one feed unit and another.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The feed unit described is most useful in feeding hard to feed materials in particulate form from a compacted mass of material in block or stick form. FIG. 1 illustrates one use of the feed unit 1 in conjunction with a concrete pump 2, the feed unit feeding the quick-set additive as a finely divided powder suspended in a fluid medium through conduit 3 intersecting conduit 4 through which wet concrete is metered. The feed unit may also be used for feeding other difficult to feed materials which, because of their physical properties, are difficult to feed accurately and/or at a uniform rate. The concrete pump, shown in phantom in FIG. 1, forms no part of this invention, but is described in US. Pat. No. 3,180,272. The feed unit described may also be used in conjunction with a conventional dry type spraying apparatus, such as Gunite, wherein the quickset additive would be introduced into the air fed dry concrete in advance of the spray nozzle where water is added to the mixture.

The feed and metering unit comprises a frame 10 on which are mounted horizontally oriented material guide cylinders 11 and 12 held in spaced relation by spacer 13. The open ended cylinders 11 and 12 communicate at one end with cylindrical extensions 14 secured around openings in the cylindrical walls 15 of the abrading wheel housing 18, each provided with a top wall 16 and bottom wall 17. Each abrading wheel 27 is mounted on a shaft 19 journalled for rotation in the housing 15. The shaft 19 is offset relative to the vertical axis of housing 15. Shaft 19 extends up through the top plate 16 of each housing and through suitable bearings 20 and seals 21 carried by housing 22 and held in place by retainer ring 22a. The splined upper shaft portion 24 of each shaft is connected to a hydraulic motor 25 mounted in housing 26. The abrading member 27 of the abrading wheels may be any material capable of eroding away the compacted material as a particulate material such as a stacked seriesof spaced apart'wire brushes secured about shaft 19. The diameter of the abrading members is less than the inner diameter of housing 15. Inlet and outlet ports 28 and 29 extend through the top and

bottom plates

16 and 17 of the abrading wheel housings and may be located as illustrated in FIG. 3. The inlet and outlet ports may be directly opposed or laterally offset. The abrading wheel may be rotated in either direction but is preferably rotated in a clockwise direction as illustrated by FIG. 3. Inlet conduits 30 are connected between a source of compressed gas (air) and the inlet ports 28. Outlet conduits 31 connected to outlet ports 29 intersect to form conduit 3 which intersects with the concrete stream flowing through conduit 4. Compressed air or other fluid medium is provided to the inlet port at suitable pressures ranging from to 200 psi. An air inlet 61 connected to the air supply entering through conduit is preferably provided adjacent the hub of the abrading wheel housing to prevent accumulation and build-up of the powdered additive in that area.

A compacted mass of material 60 is placed in one of the guide cylinders 11. The outer diameter of the compacted material is made slightly less than the inner diameter of the guide cylinders for ease of insertion of the material. The material is advanced into contact with the abrading wheel by a loosely fitting plunger 32 connected to a hollow push rod 33 which extends the length of the guide cylinder and out through an opening in cap 34 secured to the end of the guide opposite the abrading wheel housing by fasteners 34a extending through

flanges

35 and 36. A projecting shoulder 37 of the cap, having an outerdiameter approximately the same as the inner diameter of the guide cylinder, includes a recessed O-ring 38 to seal the guide cylinder against loss of air pressure. Bearings 39 are provided for the push rods 33, these being held in a recess of the cap 34 by a retainer ring 40 and snap ring 41. Seals 42 around the push rod prevent loss of gas pressure within the guide cylinder. The end of the push rod extending beyond the cap 34 is secured tothe piston 43 of hydraulic cylinder 44 by linkage 45. As the piston 43 is retracted, the compacted material in the guide cylinder is advanced by plunger 32 and push rod 33 into contact with the abrading wheel at a predetermined rate.,The rate of advance may be varied by connecting the hydraulic cylinders to a variable hydraulic pump (see FIG. 5). When the piston 43 of the cylinder 44 reaches the end of its stroke, control means (FIG. 5) are provided to activate the adjacent mounted unit to provide uninterrupted feed of the material to the use location. While the adjacent feed unit is working, the cap 34 of the empty guide cylinder is disconnected from linkage 45, cap 34 removed and the plunger 32 and push rod 33 removed to insert another compacted mass of material into the empty guide cylinder. Air inlets 62 through guide cylinders 11 and 12 are connected to the air supply entering through conduit 30 to prevent accumulation of the powdered additive in the guide cylinders behind the pistons 32. I

Referring to FIG. 5, cam operated spool valves control activation of the dual side-by-side feed units. The control system on the right is shown in activated position while the control system on the left is in inactive position. Shift of cam operated valve 50 to the position shown effects shifting of air operated valve 51 which, in turn, shifts four-way air operated valve 51 which, in turn, shifts four-way air operated valve 52, relay valve 53, and spring-centered, four-way air actuated valve 54 to (l) initiate retraction of the piston 43 of hydraulic cylinder 44, (2) furnish compressed gas through line 55 and valve 53 to the cylindrical housing, and (3) start hydraulic motor 25' powering the abrading wheel 18. The rate of retraction of piston 43 is controlled by a variable pump 50 to control the feed rate of the particulate material. When the piston has reached the end of its stroke and the compacted mass of material is about exhausted spool valve 50 is shifted to exhaust position and spool valve 56, controlling activation of the duplicate unit, shifted to the active position. Shift of valve 56, in turn, effects shifting of air operated four-way valve 52, relay valve 57, and spring-centered, four-way 4 air operated valve 58 for operation of the duplicate unit in the same manner as previously disclosed.

Quick-set additives for wet or dry concrete in uncompacted form are generally fluffy, hygroscopic materials which, on compaction under suitable pressures, form a compacted mass of material which is self-binding. The material is compressed into sticks approximately the length and diameter of the guide and cylinder of the feed unit (about 4 inches in diameter and 6 feet in length). It has been determined that two six-foot long sticks of the quick-set additive will furnish sufficient additive for operating a concrete pump of the type illustrated in FIG. 1 for about 1 hour. The pressure needed to compact the material into stick form varies depending on the particular material used. If necessary, a binder, which does not affect the end use of the product, may be added to material.

I claim:

1. In a system for applying a stream of wet, semi-fluid material setting to a hard end-product within seconds after ejection from a nozzle onto a work surface, the system including a pump metering and pumping a predetermined amount of the semi-fluid material to a discharge nozzle, and metering unit for metering and delivering a dry, particulate, quick-set additive for the semi-fluid material into contact with the stream of semi-fluid material in a predetermined weight ratio of additive to semi-fluid material, the improvement comprising providing a metering and feeding unit converting a compacted mass of the quick-set additive to a particularized state and feeding the same into contact with the stream of semi-fluid material suspended in a flow of pressurized gas, the unit comprising:

a housing having inlet and outlet ports therein,

a source of pressurized gas connected to the inlet port,

conduit means connecting the stream of semi-fluid material, abrasive means mounted for rotation within the houspower means for rotating the abrasive means,

means continuously advancing a compacted mass of the quick-set additive into contact with the rotating abrasive means to particularize the compacted additive,

the pressurized gas entering the housing through the inlet port entraining the particularized additive therein and conducting the additive suspended in the flow of pressurized gas out of the housing into contact with the stream of semi-fluid material through the conduit means.

2. The system of claim 1 wherein the abrasive means includes an abrading wheel mounted on a shaft, the wheel having a diameter less than the internal diameter of the housing and mounted for rotation within the housing with its axis laterally offset from the axis of the housing.

3. The system of claim 1 wherein the means advancing the compacted mass is adapted to move at a uniform, controlled rate.

4. The system of claim 2 wherein the means for advancing the compacted mass includes (1) a cylindrical guide chamber holding the compacted additive communicating at one end with the housing and disposed so that its axis intersects the axis of the housing perpendicularly, (2) closure means at the opposite end of the guide chamber providing access to the chamber and outlet port with the sealing the chamber from the surrounding atmosphere,

and (3) fluid power means including a plunger extending through the closure means and contacting the compacted mass within the guide chamber so as to advance the mass into contact with the rotating abrading wheel at a predetermined rate to convert the compacted mass to particularized form.

5. A system for spraying a continuous stream of wet, semi-fluid material setting to a hard end-product within seconds after ejection from a nozzle for application on a surface, the system including a pump for metering and pumping predetermined amounts of the semi-fluid material to the nozzle and a metering unit for metering and delivering a dry, particulate, quick-set additive for the semi-fluid material into contact with the stream of semi-fluid material prior to discharge from the nozzle, the improvement comprising a metering unit converting a compacted mass of the quick-set additive to particularized form for delivery suspended in a flow of pressurized gas into contact with the stream of semifluid material, the unit comprising:

a cylindrical housing having inlet and outlet ports therein,

a source of pressurized gas connected to the inlet port,

an abrading wheel mounted on a shaft journalled for rotation about an axis laterally offset from the axis of the housing,

power means for rotating the abrading wheel,

a cylinder holding a compacted mass of the quick-set additive communicating with the housing and disposed so that its axis intersects the axis of the cylindrical housing perpendicularly,

closure means at the opposite end of the cylinder providing access to the cylinder and sealing the cylinder from the surrounding atmosphere,

fluid power means including a plunger extending through the closure means and contacting the compacted mass of quick-set additive within the cylinder for advancing the compacted mass of the quick-set additive into contact with the rotating abrading wheel at a predetermined rate to convert the compacted mass to particularized form,

the pressurized gas entering through the inlet port entraining the particularized additive in the gas stream and conveying it suspended in the flow of pressurized gas into contact with the stream of semi-fluid material.

6. The system of claim 5 wherein the abrading wheel is a cylindrical wire brush.

7. Duplicate units in side-by-side relation for converting a mass of compacted quick-set additive for wet or dry concrete to a particulate state and feeding the same suspended in a flow of pressurized gas into contact with the concrete, comprising:

a material guide chamber holding the compacted additive,

a housing mounted ajdacent the chamber having an opening therein communicating with the interior of the chamber for advance of the compacted additive thereinto,

an abrading wheel mounted in the housing for eroding away the portion of the compacted additive contacting the outer circumferential surface thereof as a finely divided material,

power means operating the abrading wheel,

inlet and outlet ports through the housing adjacent the area of contact of the compacted additive and abrading wheel,

means providing a pressurized gas to the inlet port for delivery of the powdered additive eroded from the compacted mass through the outlet port in admixture with the pressurized gas,. variable rate feed means to advance the compacted additive into contact with the abrading wheel, and

control means fordeactivating one unit and simultaneously activating the adjacent unit for continuous,

uninterrupted feed of the additive.

8. A method of applying quick-setting concrete to a work surface, comprising:

pumping a stream of wet, semi-fluid concrete to a discharge area for discharge from a nozzle onto the work surface,

metering a predetermined amount of a particulate quick-set additive for the concrete suspended in a flow of pressurized gas into contact with the stream of semi-fluid material prior to discharge thereof onto the work surface by (a) abrading a compacted mass of the quick-set additive to convert a portion thereof to particularized form at a predetermined rate, and (b) feeding the particularized additive suspended in a flow of pressurized gas into the stream of semi-fluid concrete.

Claims

1. In a system for applying a stream of wet, semi-fluid material setting to a hard end-product within seconds after ejection from a nozzle onto a work surface, the system including a pump metering and pumping a predetermined amount of the semi-fluid material to a discharge nozzle, and metering unit for metering and delivering a dry, particulate, quick-set additive for the semi-fluid material into contact with the stream of semi-fluid material in a predetermined weight ratio of additive to semifluid material, the improvement comprising providing a metering and feeding unit converting a compacted mass of the quick-set additive to a particularized state and feeding the same into contact with the stream of semi-fluid material suspended in a flow of pressurized gas, the unit comprising: a housing having inlet and outlet ports therein, a source of pressurized gas connected to the inlet port, conduit means connecting the outlet port with the stream of semi-fluid material, abrasive means mounted for rotation within the housing, power means for rotating the abrasive means, means continuously advancing a compacted mass of the quick-set additive into contact with the rotating abrasive means to particularize the compacted additive, the pressurized gas entering the housing through the inlet port entraining the particularized additive therein and conducting the additive suspended in the flow of pressurized gas out of the housing into contact with the stream of semi-fluid material through the conduit means.

4. The system of claim 2 wherein the means for advancing the compacted mass includes (1) a cylindrical guide chamber holding the compacted additive communicating at one end with the housing and disposed so that its axis intersects the axis of the housing perpendicularly, (2) closure means at the opposite end of the guide chamber providing access to the chamber and sealing the chamber from the surrounding atmosphere, and (3) fluid power means including a plunger extending through the closure means and contacting the compacted mass within the guide chamber so as to advance the mass into contact with the rotating abrading wheel at a predetermined rate to convert the compacted mass to particularized form.

5. A system for spraying a continuous stream of wet, semi-fluid material setting to a hard end-product within seconds after ejection from a nozzle for application on a surface, the system including a pump for metering and pumping predetermined amounts of the semi-fluid material to the nozzle and a metering unit for metering and delivering a dry, particulate, quick-set additive for the semi-fluid material into contact with the stream of semi-fluid material prior to discharge from the nozzle, the improvement comprising a metering unit converting a compacted mass of the quick-set additive to particularized form for delivery suspended in a flow of pressurized gas into contact with the stream of semi-fluid material, the unit comprising: a cylindrical housing having inlet and outlet ports therein, a source of pressurized gas connected to the inlet port, an abrading wheel mounted on a shaft journalled for rotation about an axis laterally offset from the axis of the housing, power means for rotating the abrading wheel, a cylinder holding a compacted mass of the quick-set additive communicating with the housing and disposed so that its axis intersects the axis of the cylIndrical housing perpendicularly, closure means at the opposite end of the cylinder providing access to the cylinder and sealing the cylinder from the surrounding atmosphere, fluid power means including a plunger extending through the closure means and contacting the compacted mass of quick-set additive within the cylinder for advancing the compacted mass of the quick-set additive into contact with the rotating abrading wheel at a predetermined rate to convert the compacted mass to particularized form, the pressurized gas entering through the inlet port entraining the particularized additive in the gas stream and conveying it suspended in the flow of pressurized gas into contact with the stream of semi-fluid material.

7. Duplicate units in side-by-side relation for converting a mass of compacted quick-set additive for wet or dry concrete to a particulate state and feeding the same suspended in a flow of pressurized gas into contact with the concrete, comprising: a material guide chamber holding the compacted additive, a housing mounted ajdacent the chamber having an opening therein communicating with the interior of the chamber for advance of the compacted additive thereinto, an abrading wheel mounted in the housing for eroding away the portion of the compacted additive contacting the outer circumferential surface thereof as a finely divided material, power means operating the abrading wheel, inlet and outlet ports through the housing adjacent the area of contact of the compacted additive and abrading wheel, means providing a pressurized gas to the inlet port for delivery of the powdered additive eroded from the compacted mass through the outlet port in admixture with the pressurized gas, variable rate feed means to advance the compacted additive into contact with the abrading wheel, and control means for deactivating one unit and simultaneously activating the adjacent unit for continuous, uninterrupted feed of the additive.

8. A method of applying quick-setting concrete to a work surface, comprising: pumping a stream of wet, semi-fluid concrete to a discharge area for discharge from a nozzle onto the work surface, metering a predetermined amount of a particulate quick-set additive for the concrete suspended in a flow of pressurized gas into contact with the stream of semi-fluid material prior to discharge thereof onto the work surface by (a) abrading a compacted mass of the quick-set additive to convert a portion thereof to particularized form at a predetermined rate, and (b) feeding the particularized additive suspended in a flow of pressurized gas into the stream of semi-fluid concrete.