US2795406A

US2795406A - Means for applying concrete

Info

Publication number: US2795406A
Application number: US451523A
Authority: US
Inventors: Theodore R Vessels
Original assignee: Steam-Cote Corp
Current assignee: Steam-Cote Corp
Priority date: 1954-08-23
Filing date: 1954-08-23
Publication date: 1957-06-11
Anticipated expiration: 1974-06-11

Description

June 11, 1957 Filed Aug. 23, 1954 T. R. VESSELS MEANS FOR APPLYING CONCRETE 3 Sheets-Sheet l June 11, 1957 1-. R. VESSELS 2,795,405

MEANS FOR APPLYING CONCRETE Filed Aug. 23, 1954 5 Sheets-Sheet 2 INVENTOR. WfiO/JOEE/Q M35525 BY ma Cub hwy June 11, 1957 'r. R. VESSELS 2,795,406

MEANS FOR APPLYING CONCRETE Filed Aug. 23, 1954 3 Sheets-Sheet 3 I Z I Z 9 f I I I I x! i 8 .3 17,10" 9 INVENTOR. 7715000258 Mssazzs United States Patent MEANS FOR APPLYING CONCRETE Theodore R. Vessels, Escondido, Calif., assignor to Steam-Cote Corporation, Escondido, Calif., a corporation of California Application August 23, 1954, Serial N 0. 451,523

19 Claims. (Cl. 259-451) My invention relates to means of applying concrete, and is a continuation-in-part of my application, now abandoned, entitled Means and Method of Bonding Concrete to Steel, Serial No. 195,166, filed November 13, 1950, and is a continuation-in-part of my copending application entitled Method of Applying Concrete, Serial No. 246,425, filed September 13, 1951, now Patent No. 2,696,353 granted Dec. 7, 1954, and is also a continuation-in-part of my copending application entitled Means for Applying Concrete, Serial No. 315,271, filed October 17, 1952, now abandoned.

Included in the objects of my invention are:

First, to provide a means of applying concrete wherein the sand-cement mixture is delivered to one or a series of nozzles in a free-falling cascade at a predetermined rate and is entrained in one or more steam-water jets.

Second, to provide a means of applying concrete which is particularly applicable for coating metal pipe to produce concrete-clad metal pipe, or the coating of a collapsible mandrel to produce concrete pipe.

Third, to provide a means of applying concrete wherein steam may be employed as the jet-propelling force to entrain and drive a cement-sand-water mixture at high velocity against the surface to be coated, whereby the surface is thoroughly cleaned simultaneously with the initial coating, whereby hydration is accelerated by the action of the' hot steam so that the object coated, such as a pipe, may be handled immediately, and whereby curing time is reduced to a minimum.

Fourth, to provide a means of applying concrete where-- in one form of said means is designed primarily for the purpose of applying a series of concrete coatings or lamina tions to a metal pipe to produce a concrete-clad pipe, or the applying of concrete laminations to a collapsible mandrel;

or form in the manufacture of concrete pipe.

Fifth, to provide a means of applying concrete \lami nations wherein a series of closely grouped nozzles apply the several laminations simultaneously as a pipe or mandrel is passed in front of the nozzles, and wherein the character of the laminations, immediately as applied, is

such that the underlying laminations withstand such loads as may be inherent in the wrapping of steel wire reinforcing; thus, reinforcing Wire may be wrapped simultaneously with the application of the laminations.

Sixth, to provide a novel means of this class wherein a plurality of nozzles entrain and mix steam, water, sand,

and cement; and wherein the relative amounts of waterin the different jets may be varied to control the relative moisture content of the several jets, thus enabling the coating of metal pipe under conditions in which the initial coating may have a deficiency of water to facilitate bond-- Eighth, to provide a means of applying concrete which incorporates a novel feed arrangement for the powdered and granular solids, i. e., sand and cement, which not only affords accurate measurement or proportioning of the solids, but also ensures proper dispersion of the solid particles before being entrained by the steam and water so that the resulting mixture is completely homogeneous.

Ninth, to provide in a concrete applying means a novel feed arrangement which is not dependent, in its operation, upon dry sand and cement, but may use a sand and cement mixture having an appreciable moisture content without impairing operation of the apparatus.

With the above and other objects in view, as may appear hereinafter, reference is directed to the accompanying drawings, in which:

Figure 1 is a top or plan view of one form of my a p-.

paratus for applying concrete;

Fig. 2 is a partial sectional, partial elevational view thereof, taken through 22 of Fig. 1;

Fig. 3 is a partial sectional, partial front elevational view thereof, taken from the line 3-3 of Fig. 2;

Fig. 4 is an enlarged sectional view taken through 4 4 Fig. 9 is a fragmentary sectional view thereof, taken through 99 of Fig. 6.

Reference is first directed to Figs. 1 through 5. My-

apparatus for applying concrete, as herein shown, includes a pair of side frame members 1, preferably formed of angle iron, spaced with their upright flanges in confronting relationship to define a channel. The side frames are suitably mounted on a framework (not shown). Disposed under the side frames and bridging the channel therebetween is a conveyor belt 2, the upper reach of which is in sliding contact with the underside of the frame members 1. The conveyor belt 2 is mounted on rollers 3, journaled by bearings suspended under the frame members. The rearward roller is provided with drive mean-s4 which may comprise a motor, gear drive, and chain linkage Mounted above the side frames 1 is a hopper 5 having 7 a discharge end directed between the side frames. The conveyor belt 2 forms a closure for the lower end of the hopper. The forward side of the hopper is provided between the. side frames 1 with a vertically adjustable gate 6, which may be raised and lowered by elevator means 7, comprising a hand-operated shaft, gear, and

rack means. The position of thelower edge of the gate j 6 above the conveyor belt determines the thickness of the layer of material which may be withdrawn from the hopper as the belt is driven.

It is intended that the hopper 5 contain a sand-cement 7 mixture; that is, a mixture of sand and hydraulic or Portland cement. It is not necessary that the sand be dried or otherwise especially treated to remove its normal moisture content. This is of primary importance, for the reason that heretofore it has been necessary at substantial expense to maintain the sand in a dry, free-flowing state in order to apply the solid material by convenj block 9. The manifold block is provided with a series .of vertical bores intersected by a common distributor 3 chamber which is directed laterally. Each vertical bore receives an inner nozzle element or liner 11 which is sealed in the upper side of the valve structure and projects downwardly across the distributor chamber. Below the distributorchamber each vertical borefonns with its inner nozzle an annular passage 12.

Secured to the under side of the manifold bloek 9 is a plurality of orifice plates 13, one for each inner nozzle. Each orifice plate isprovided with a central opening which surrounds the lower extremity of the corresponding inner nozzle to form therewith an annular steam orifice 14, Fig. 4.

For reasons which will be brought out hereinafter, the orifice 14 must be truly concentric with the inner nozzle 11 and of uniform width throughout its periphery. This is made possible by the lateral adjustment provided at the oppositely directed mounting lugs 15 having mounting holes which loosely receive bolts or studs 16 screwed into the underside of the manifold block 9. In order to center each orifice plate, a gauge 17, Fig. 5, isprovided. The gauge has a tubular end adapted to slide over an inner nozzle 11 and fit slidably within the opening in the corresponding plate. As shown in Fig. 5, by positioning the gauge between the nozzle 11 and orifice plate 13 while the bolts 16 are loose, the plate may be positioned in exact concentricity and the bolts then tightened.

Each orifice plate 13 is provided with a depending annular boss concentric with its opening and adapted to receive an outer nozzle element or tube 18. Thus, nozzle elements 11 and 18 comprise an open-ended upright, or downwardly directed, nozzle structure provided with an orifice 14 in a zone or region intermediate the ends thereof.

The upper side of the manifold block 9 supports a funnel structure 19, the upper part of which fits in front of and embraces the discharge end of the conveyor so as to collect all the sand-cement mixture delivered thereby. The lower portion of the funnel structure 19 is divided into a series of funnel units 20, one registering with each inner nozzle 11 so that the sand-cement mixture is equally distributed.

Secured to the manifold block 9 and communicating with the distributor chamber 10 isa steam chest 21. The side walls of the steam chest converge to a tubular extendedend which is joined to a steam valve 22. The

steam valve is supplied with steam, preferably through a flexible hose 23.

A water nozzle 24 projects into the steam chest 21 near the steam valve 22 through a packing gland 25. The water nozzle is connected to a water valve 26. The water nozzle is provided with a laterally directed orifice or orifices to deliver a stream of water toward the series of inner nozzles 11. The water nozzle is rotatable so that the relative quantities of water delivered to the series of nozzles may be varied.

The steam valve and water valve arepreferably supplied through hoses so that the entire manifold structure may be moved between its normal position in which the nozzles are directed vertically downwardly to an inclined position indicated by dotted lines in Fig. 2.

Operation of my apparatus is as follows: Steam and water are supplied to the steam chest and distributor chamber and caused to jet downwardly through the outer nozzle tubes 18, creating a negative pressure in the inner nozzles 11 and funnel 19. Simultaneously, the conveyor belt carries a sand-cement mixture to the funnel 19 where such mixture falls by gravity, aided by the negative pressure produced at the discharge ends of the inner nozzles. The sandcement mixture is entrained with the steam and water as it passes through and discharges at high velocity from the outer nozzles 18. A pipe or other surface to be coated is rotated and passed underneath the discharge ends of the nozzles 18, the direction of movement being in the common plane of these nozzles.

ltshould be observed that the sand-cement mixture contained in the hopper maybe formed with sand containing a normal amount of moisture, that is, the sand may be used as it comes normally from a storage bin even though it may be damp. This is of primary importance for the reason that the cost of drying sand and maintaining it in such condition is substantial.

The use of damp sand is made possible by the unique arrangement of the conveyor belt 2 which wipes across the underside of the storage bin to withdraw a layer of the sand-cement mixture, coupled with the arrangement wherein the sand-cement mixture is poured by gravity from the discharge end of the conveyor and caused to fall unconsolidated and freely into the funnel 19. The sand-cement mixture does not accumulatein the funnel, but is immediately entrained in the downwardly flowing air created by the jetting action of the steam, and thus accelerated to a high velocity by the steam jet. It should be observed that prior to any influence of the steam jet itself, the sand-cement mixture is accelerated by gravity action so that the steam jet is not required to accelerate the solid material from zero velocity, but from a substantial initial velocity.

It will be observed that the sand-cement mixture is maintained principally in the central portion of the discharging column of the sand, cement, water, and steam so that the inner walls of the nozzles 13 are continually washed by the steam and Water and accumulations of cement are avoided. This condition obtains only if the annular steam orifice 14 is truly concentric with the inner nozzle 11; otherwise, wear, due to the a-brading action of the sand-cement mixture, will quickly destroy the outer nozzle as well as interfere with proper application of the mixture to the surface to be coated.

The steam is not only more economical to produce than compressed air, but has several additional advantages. The steam virtually eliminates any dust. If air is used a large quantity of dust is produced. This dust consists largely of cement, which is not only lost but constitutes a working hazard for the operator, requiring the use of a respirator mask. As will be brought out in more detail hereinafter, the high temperature of the steam materially improves hydration and substantially reduces curing time. However, my apparatus is capable of successful operation by use of air in place of steam.

Adjustment of the water supply, not only as to its total volume but also as to its distribution to the several nozzles, is of primary importance. For instance, in the applying of-concrete laminations to steel pipe, a moisturedeficiency first coating is desired, whereas in the forming of concrete pipe over a collapsible mandrel a greater moisture content is desired.

Considering first the coating of steel pipe, it has been found that by use of a moisture-deficiency first coating a remarkably tenacious bond is obtained. Byuse of a moisture-deficient steam-jetted mixture of sand and ccment'delivered at high velocity, a scouring action is obtained which thoroughly cleans the pipe. A large percentage of the sand rebounds from the pipe so that the resulting coating has a concentration of fines and cement. Most of the cement remains to coat the pipe, for the sand, which rebounds, is virtually free of cement coating and is capable of being salvaged for reuse. This scouring action, coupled with the immediate application of the cement, eliminates any oxide coating which would reduce bonding between the concrete and the pipe.

In the jet application of the laminations, there is a tendency for the water content to concentrate at the radially inner surface; thus, the moisture content of the first coating or lamination tends to collect on the surface of the pipe and prevents a good bond between the cement and the pipe. By providing a moisture-deficient first layer any concentration of moisture at the surface of the pipe is immediately drawn back into the lamination. To ensure complete hydration of th'einitial lamination the second and third laminations are not moisture dc ficient, but may contain a slight excess for absorption into the initial lamination. v i

It has been found desirable to provide a moisturedeficient final coat or lamination, although this is not as vital as in the case of the first coating. p

In the manufacture of concrete pipe wherein the laminations are applied overa collapsible mandrel, it is desirable to produce a moisture layer between the first coating and the mandrel. Consequently, instead of providing a moisture-deficient first coating, an adequate quantity of water is supp-lied to produce a moisture film which will avoid any bonding and facilitate removal of the mandrel. it should be understood that in any case the moisture content of the various laminations is held to a minimum so that the resulting mixture is damp rather than Wet. It has been found that with proper control of the moisture content coupled with the action of the steam to promote hydration of initial setting, the concrete pipe or concreteclad metal pipe may be handled immediately after being coated. By handling it is meant that the pipe may be removed from the carriage or other means whereby it is moved past the nozzles and placed on runners or other supports, and that within a very short time the pipe may be stacked for storage without danger of injury to the concrete.

It will be observed that the nozzles are closely grouped so that as the pipe or mandrel is moved past the nozzles each lamination is exposed for only a matter of seconds before the succeeding lamination is applied. Even though this be the case, initial setting of the concrete takes place so rapidly that it is possible to apply wire reinforcing simultaneously with the application on the concrete mixture. Heretofore, it has been necessary to apply initial laminations, allow the laminations to cure partially, and

then apply the wire reinforcing and outer laminations. This has required double handling of the pipe, whereas in the present instance both coating and reinforcing are accomplished simultaneously.

It will be observed that the amount of war-er supplied through the water nozzle is adjusted to compensate for the initial moisture content of the sand. In addition, it will be observed that the relative volume of water supplied to each of the nozzles is easily regulated by turning the water supply nozzle. In order to facilitate adjustment and in order to avoid coating of the pipe during return movement of the carriage or other structures (not shown) which supportsthe pipe, the entire manifold or nozzle assembly may be tilted to the dotted line position shown in Fig. 2.

While a belt conveyor is shown, it should be observed that a screw conveyor may be used, providing that uniform quantities of sand and cement are delivered to and permitted to fall freely into and through the funnels.

Reference is now directed to the modified nozzle structure shown in Figs. 6 to 9, inclusive. The construction here shown difiers from the previously described structure, principally in that a single elongated nozzle is provided in place of the four separate nozzles.

-A manifold 31 is provided in which is formed a vertical slot 32. At opposite sides of the vertical slot there is provided a pair of triangular steam chambers 33 having downwardly directed orifice slots 34 closely adjacent the vertical slot 32. The steam chambers are connected to a supply pipe 35 through U-shaped branch pipes 36; The supply pipe 35 is provided with a suitable steam valve, as in the first described structure. Also, as in the first described structure, there is provided (a water nozzle 24 located at the juncture of the supply pipe 35 with the supply branches 36. The manifold 31 may be supported under the discharge end of a conveyor 2, in the same manner as the first described structure, or-mray be rigidly mounted.

Secured to the upper side of the manifold 31, in registry with the vertical slot 32, is an intake funnel 37 shaped to embrace the discharge end of the conveyor so that the sand and cement may fall freely in to the intake funnel and be guided into the vertical slot 32. I

Secured to the underside of the manifold 31 is a dis charge nozzle 38 defining in cross section a rectangular discharge passage of sufficient width to embrace both the vertical slot 32 and the orifice slots 34.

Operation of my modified nozzle structure is as follows:

The nozzle structure is disposed longitudinally with respect to the pipe or other surface to .be coated, that is, the nozzle is movedcdgewise along such surface.

The concrete mixture is applied in the same manner as the first described structure except that there is a continuous building up of the cement coating rather than the formation of laminations.

Due to the fact that the water particles have a greater mass than the gaseous steam, there is a tendency for the moisture to be greatest at the central portion of the nozzle. This is desirable, particularly in the coating of pipe, for, (as pointed out in connection with the first described structure, the portion of the concrete mixture first to engage the pipe should be somewhat moisture deficient to improve the scouring action and prevent the formation of a water film between the concrete and the pipe, whereas the succeeding portions of the concrete may have slightly excess moisture content and the final portion may again be slightly deficientin moisture. However, by proper shaping of the steam'chest and use of additional water nozzles any desired distribution of moisture along the length of the discharge nozzle may be attained.

It should again be emphasized that in both the constructions shown the cement-sand mixture falls free through the funnel and nozzle structure and is initially accelerated by gravity and by the downward flow of air through the funnelbefore impelled by the steam jets. This results in a thorough mixing of the ingredients even though the time element between the introduction of the steam and water and contact with the pipe is extremely short.

'It should be observed that in the coating of pipe it is sometimes desirable to provide a wrapping of reinforcing wire. The wire may be fed under the nozzle at any intermediate portion, as indicated by W in Fig. 8.

Having fully described my invention, it is to be understood that I do not wish to be limited to the details herein set forth, but my invention is of the full scope of the appended claims.

I claim:

I. An apparatus for applying concrete to surfaces, compnslng: a hopper for a sand-cement mixture; a belt conveyor positioned to pass under said hopper to withdraw laterally a layer of said sand-cement mixture and cause the mixture to fall freely by gravity therefrom; an openended uncurved relatively short nozzle structure positioned below the discharge end of said conveyor to receive the free falling mixture from said conveyor; and a motive fluid-water manifold communicating with said nozzle structure and defining therewith at least one jet orifice for producing a jet to entrain said mixture and become cornmjngled therewith, and to propel the same for discharge at high velocity from the nozzle structure.

2. An apparatus as set forth in claim 1, wherein: said nozzle structure comprises a plurality of jet orifices arranged in a row.

3. An apparatus as set forth in claim 1, wherein: said nozzle structure comprises a plurality of jet orifices arranged in a row; and means is provided to vary the relative quantity of water delivered to said jet orifices.

4. An apparatus as set forth in claim 1, wherein: said nozzle structure includes a single jet orifice in the form of an elongated slot.

5. An apparatus for applying concrete to surfaces, comprising: a hopper for a sand-cement mixture; a belt conveyor positioned to pass under said hopper to withdraw laterally a layer of said sand-cement mixture and to 7 discharge the mixture to fall freely by gravity therefrom; an open-ended uncurved.relativelyshort downwardly directed nozzle structure, havinga guiding funnel at its upper end positioned to guide said free falling mixture as discharged from said conveyor into said nozzle structure; and a motive fluid-water manifold communicating with said nozzle structure and defining therewith at least one jet orifice for producing a jet to entrain said mixture and become commingled therewith, and to propel the same for discharge at high velocity from the nozzle structure.

6. An apparatus as set forth in claim 5, wherein: said nozzle structure comprises a plurality of jet orifices arranged in a row.

7. An apparatus as set forth in claim 5, wherein: said nozzle structure comprises a plurality of jet orifices arranged in a row, and means is provided to vary the relative quantity of water delivered to said jet orifice.

8. An apparatus as set forth in claim 5, wherein: means is provided to vary the relative quantity of water delivered to said jet orifices.

9. An apparatus for applying concrete to surfaces, comprising: an open-ended relatively short substantially vertically disposed tubular downwardly directed nozzle structure having an open upper end serving as an inlet and an open lower end serving as an outlet whereby granular material may fall freely through said nozzle structure; means for jetting downwardly into the intermediate portion of said nozzle structure a steam-water mixture; a conveyor disposed for gravity discharge of an unconsolidated freely falling sand-cement mixture into the open upper end of said nozzle structure for entrainment in said steam-water jet; and means for regulating the volume of said sand-cement mixture delivered by said conveyor to. said nozzle structure.

10. An apparatus as set forth inclaim 9, wherein: said, nozzle structure comprises a plurality of jet orifices arranged in a row.

11. An apparatus as set forth. in claim 9, wherein: said nozzle structure comprises a plurality of jetorifices. arranged in a row; and means is provided to vary the relative quantity of water delivered to said jet orifices.

12. An apparatus as set forth in claim 9, wherein: said nozzle structure includes a single jet orifice in-the form of an elongated slot.

13. An apparatus for applying concrete to surfaces, comprising: an open-ended uncurved substantially vertically disposed tubular nozzle structure having the cross section of an elongated slot, said nozzle structure also having an upper open end serving asan inlet and a lower open end serving as an outlet whereby granular material may all freely through said nozzle-structure; meansfor jetting a steam-water mixture downwardly into said nozzle structure at a region intermediate its end; and means for feeding an unconsolidated freely falling sand-cement mixture into the inlet of said nozzle structure for entrainment into said steam-water jets and for. discharge. from said nozzle structure at high velocity.

14. An apparatus for applying concrete, comprising: means for producing a'free falling column of unconsolidated sand and cement; means for guiding said column in a substantially straight path; and a steam-water jet in said guiding means foraccelerating said sand and cement and mixing therewith for impingement against a surface; said guide means being an open-ended vertical tube, its cross section defining an elongated slot, said steam-Water jet being located in the opposite sides of said tube and directcd. downwardly.

15. An apparatus for applying concrete, comprising: means for producing a free falling column of unconsolidated-sand and cement; means for guiding said column in a substantially straight path; and a steam-water jet in saidguiding means for accelerating said sand and cement andmixing therewith for impingement against a surface; said guide means comprising a row of closely spaced vertical tubes, and said steam-water jet including an annular downwardly directed jet in each tube.

16. An apparatus for. applying concrete, comprising: means for producing a free falling column of unconsolidated sand and cement; means including a pair of fiat confronting walls of substantial lateral width for guiding said column in a substantially straight vertical path; and a steam-water jet directed downwardly to flow at high velocity in said path for accelerating said sand and cement and mixing therewith for impingement against a surface.

17. An apparatus for applying concrete to surfaces, comprising: a hopper for a sand-cement mixture; a belt conveyor having a conveying reach positioned to pass under said hopper thereby to withdraw laterally a layer of said sand-cement mixture and cause the mixture to fall freely by gravity from an end of said conveyor reach; means including flat vertically disposed confronting walls defining therebetween a passageway open at its upper and lower ends. into which said sand-cement mixture falls from said conveyor reach; and a motive fluid-water nozzle structure positioned to. jet downwardly through said passageway to entrain, commingle, and propel said sandcementmixture at high velocity from the lower end of said passageway.

18. An apparatus for applying concrete to surfaces, comprising: confronting fiat vertically disposed walls definingtherebetween a passageway open at its upper and lower ends; means for conveying a layer of unconsolidated sand and cement into the upper open end of said passage- Way to cause the sand and cement to fall freely through said passageway; and means for jetting downwardly through said passageway a steam-water mixture to inter mix with the sand and cement and propel the sand and cement at high velocity from the lower end of said passageway.

19. An apparatus for applying concrete to surfaces, comprising: confronting fiat vertically disposed walls defining therebetween a passageway open at its upper and lower ends; means for conveying a layer of unconsolidated sand and cement into the upper open end of References Cited in the file of this patent UNITED STATES PATENTS 1,170,699 Stoifel Feb. 8, 1916 2,014,708 Vawter Sept. 17, 1935 2,231,489 Anderson et al. Feb. 11, 1941 2,570,367 Mitten Oct. 9, 1951 2,577,664 Pro Dec. 4, 1951 2,696,353 Vessels Dec. 7, 1954