US1656001A - Pbocess of proportioning sand aud water bop - Google Patents

Description

Jan. 10, 1928. LESQOM c. s. JOHNSON PROCESS OF PROPORTIONING SAND AND WATER FOR CONCRETE Filed April 19. 1926 15 L343 2 T 5 9 v I 5 if 2'5 %%J/ mm M MW Patented Jan. 10, 1928.

UNITED STATES'ATENT OFFICE.

UHARLE$ S. JOHNFB'UN, 01* GHAMPILIGN, ILLINOIEE.

PROGEEB 0F PROPURTIONTNG? SAND AND WATER FOR CONCRETE.

The invention relates generally to the art of making concrete and more particularly to a method for proportioning the total amount of water in the min.

It is the object of the invention to provide a new and improved process for proportioning the total amount of water in a concrete mix, that will compensate for the normal moisture content of the sand.

It is another object ot the invention to provide an improved process for proportioning the total water in a concrete mix which is readily adapted to field worlt.

It has been recognized that the strength of concrete depends largely upon the total amount of water in the min, and it follows that accurate control of the total water in eluded in the mix is highly essential to ob tain concrete of uniform strength.

The methods heretofore used for proportioning the water in the mix have not given uniform results. In the processes used here tofore wherein the sand is measured by volume and then introduced into a concrete mix with a separately proportioned unit of water, variations in the normal moisture content of the sand. have caused variations in the total water in the min. Attempts have been made to control accurately the amount of water introduced into the mix but no process has been advanced whereby the total water'could be controlled satisfactorily withoutadjustment to compensate tor unap parent variations in the compaction of the sand.

Changes in the moisture content in commercial sand alter the apparent volume of the sand due to the resulting changes in bulking, but do not alter the absolute volume of the sand. The changes in apparent volume are not directly proportional to the changes in normal moisture content throughout the full range of possible moisture content in the sand. However, an anal ysis of the bulking characteristics of com mercial sand has disclosed that the absolute volume of sand in equal apparent volumes of moist sand is quite constant within a certain range of moisture variation, and

Serial No. 103 183.

practically uniform absolute volumes independent of the normal moisture content within this range.

I utilize these facts in providing a process for proportioning the total amount of water for a concrete mix, the process consisting generally of measuring a predetermined volume of normally moist commercial sand and then combining with that sand a quantity of water such. that the combined sand and total water equals a predetermined volume.

For the purpose of illustrating more clearly the operation of the process I have illus trated in the accompanying drawings an ap paratus adapted toutilize the process, together with diagrammatic sectional views of the apparatus at various stages in the proc lit is to be understood, however that the term of the apparatus and the arrangement of the parts may be varied at will without departing from the spirit and scope oi the invention as defined by the appended claims.

In the drawings:

Figure 1 is an elevational view of a volumetric measuring device.

Fig. 9. is a sectional view thereof at one stage of the process.

Fig. 3 is a similar view at a later stage.

Referring to the drawings, the device se lected for purposes of illustration comprises a sand bin A and an adjustable measuring hopper B. The sand bin may be suitably supported by any desired means (not shown). This bin has a circular discharge opening 1 at the bottom thereof and is provided with a gate 2 pivoted at 3 to oscillate about a vertical axis. A handle ti: on the gate serves as a means to operate the gate.

The measuring hopper B comprises an upper conical portion 5 and a lower container 6 which is generally cylindrical in form but which has inwardly sloping sides 7 at the bottom converging to define a circular discharge port 8, thereby to insure complete discharge of material from the hopper. The upper portion 5 is herein shown supported from the bin A by means of a plurality of integral brackets 9 and chains 10 which are attached at their opposite. ends to the brackets and to the bin A. The container is adjustable relative to the upper portion 5 f the hopper to permit of adjustment of i volumetric content of the l For the container in shown suspended from the brackets 9 by means of chains 11, and adjustable screw devices 12 having hooked portions 13 are provided on each bracket to receive the free end of a chain. Should it be desired to adjust the volume of the hopper to a greater extent than that provided for by the screw devices. a lower link on each chain may be caught over the hooks 13. r V

Agate "1 having :1 water tight gasket 1% is provided to control the discharge opening 8 of the hopper; This gate is carried on an arm pivotally supported intermediate its endsat i6 on a bracl-zet 17 which is secured rigidly to the container 6. The end 18 of this arm' 'is pivoted to an outstanclingilug 19 'onthe gatel' As herein illi .itratedthe arm is operable by means of a hand lever 20 pivoted-at 21 on the bracket 17, and a toggle link 22 connecting the adjacent ends of the lever 20and'arnr15. Thum in its. closed positionthe gate leis held'locked by the toggle device: I

' In'the apparatus illustrated in the draw ings--meansis provided to combine water fof'commercial' sand the hopper may be adjustedin accordance with asuitable scale (not shown)-to' measure this volume: If a predetermined quantityjof compacted sand is desired anda quantity of normally moist bulk sandis to' loe measured which will yield an equivalent amount of compacted sand,

the volume of themeasuring hopper may be setby experiment as follows "A 'hopperfulofloose 11101813 sand is disclia-rged unto a calibrated measure and therein. compacted by t a rnping, ro'dding Oll other suitable methods Should this batch oflfoose o sand yield". lefssthan the desired volume. of

compactecl-fsand,- the hopper B is adjusted to 'measurea greater volumethan before and vrc'efversa-l By Zt 'SGllGS of such GXPQI'IIHGHJES thesvo'lume of the hopper B is adjusted so as measure a quantity 10f loose normally compacted sand.

' rn oist sandcontainingthe' desired volumeof 'Withthe hopper' properly adjusted it is then necessary to set the overflow 25 at a glevel whereby the water added, combined .wi'th'the moisture in'the sand, gives a concretemix of the desired consistency. A field method well adapted for determining the proper level of the overflow, consists in making a series of experimental batches of concrete with the overflow set at different levels, until concrete of the desired consistency is obtained. Thus with the gate l-lclosed, the gate 1 on the bin A is opened by operating the handle whereupon sand from the bin discharges into the hopper until the hopper is full shown in Fig. llv closing the gate 1 the sand in the bin cut oil from the sand in the hopper, thus lcaviru, the dc sired volume of loose sand in the hopper.

Water is then admitted from the supply line by opening the hive 2i, until the water in the hopper reaches the height oi? the overflow as shown in'l ip. ll. This point is fienorally determined by allowing some water to discharge over the overflow. The valve 241- is then closed, and the experiment nl bal ch of combined sand and water is used to make a batch of concrete. ll the consistency of: the resulting" mix is other than that desired, the nuts on the bolts 26 are loosened and th overflow is raised or lowered depending upon whether the concrete was too dry or wet, By a series of such experimental hatii'hcs the overflow may be adjusted to a level which will provide the water necessary for the desired consistency of concrete providing the absolute volume of each batch oi? the ncnrcas uredloose SilllCldOES not vary. lVith the volume of the hopper B adjusted and the over flow 25 set at the selected level, the process consists of the following steps. First the predetermined volume of normally moist sa ndis measured by filling the hopper from the bin A. Water is then'admitted from the pipe 23 until it reaches the level of the overflow whereupon the valve is closed. The mass of combined sand and water is then ll-SeCl'il'l'Inl-lill'lg a batch of concrete.

It is apparent that by this process the moisture introduced into the container as moi sturc in the sand, becomes apart oi the total water andthat the total water inthe container is complementary in volume to the absolute volume of the sand. Inasmuch as the variation in absolute volume of sand measured by apparent volumes is less than the moisture variation, within the range hcrcinbe'lorc mentionechit will-be apparent that the variation in total water measured by this process will be less than that encounteredwhen water and moist sand are measured inde- --pendently and later combined in a mix.

The process isparticularly well adapted i or use with apparatus of simple construc' tion and because of its ease of operation readily lends itself to field work. When used withthe apparatus described herein, and this apparatus has once been calibrated. it ismerely necessary for an operator to open the gate on the sand bin and thereby discharge sand into the hopper until the l ll volume.

sand stops flowing, then by closing the gate he strikes oil the sand to the predetermined The valve in the water line is then opened and Water permitted to flow into the hopper until some of it overflows the outlet, whereupon by closing the valve the combined sand and Water is ready to be mixed with the proper proportions of cement and stone and may be discharged through the gate on the hopper.

I claim as my invention:

1. A process for proportioning the total Water in a concrete mix which comprises measuring a predetermined volume of normally moist sand and combining water with said measured sand until the combined sand and total Water equals a second predetermined volume.

2. A process for proportionintl the water in a concrete mix which comprises placing a premeasured quantity of normally moist sand in a container and flowing Water up- Wardly through the sand to a predetermined level.

3. In a process for making concrete mixtures, the step of proportionin g the total Water as a complementary volume to the absolute volume of premeasured normally moist bulk sand.

4.. The process of making concrete mixtures which consists in measuring by apparent volume a quantity of normally moist commercial or bulk sand sufficient to equal substantially a predetermined absolute volume, and then adding water to said measured sand to produce a predetermined combined volume.

5. In concreteconstruction, the process of measuring the sand and Water for the mix which consists in introducing moist bulk sand into a hopper having a Water outlet located at a predetermined level, striking oil the excess sand at a predetermined point above said water outlet, admitting Water to the hopper from a point below said outlet until a quantity is free to run ott through the outlet, and finally discharging the combined sand and water from the hopper.

6. The process of making concrete which includes a step of combining water and a quantity of bulk sand having a variable moisture content until the combined elements attain a predetermined volume as determined by the predetermined proportions of the elements to constitute the mix.

In testimony whereof, I have hereunto affixed my signature.

CHARLES S. JOHNSON.

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