US1885645A - Cement gun nozzle - Google Patents

Description

1, 1932. J. T. VAWTER CEMENT GUN NOZZLE Nov.

Filed Jan. 4, 1930 2 Sheets-Sheet {/I/I/Z/TOB JOHN TKvwrse NOV. 1, 1932. I J v w 1,885,645

CEMENT GUYN NOZZLE Filed Jan. 4. 1950 2 Sheets-Sheet 2 MKQl TO N 77%, WTEg HTTOlB/VEV Patented Nov. 1, 1932 JOHN T. vnwrnmor Los ANGE-LES, oemronnm CEMENT GUN NOZZLE Application 'filed. January 4, 1930. Serial No. 418,489.

This invention relates to cement gun nozzles and deals with the rebound of particles and the erosion of working surfaces occurring during the depositing of hydrated concrete mixtures upon surfaces by pneumatic means.

The phenomenon of rebound in depositing cementitious materials by cement gun equipment is well known to users of the cement gun. The degree or amount of rebound is proportional to the density of the work desired and ranges between a necesing and compacting the deposited mass. But

where the density required is not above that of the average hand work, the rebound of material becomes a nuisance'and an expensive waste of time and material. The control of rebound, therefore, becomes a paramount consideration to users of the cement gun. Rebound, as the word is used in this instance, is intended to include the particles reflected from the surface of deposition by incident velocity and alsothose particles already deposited, thatare swept from the surface by the velocity of the released air. The firstdeals with the ballistic properties of the material particles and the latter may be' termed air erosion. Air erosion as it is applied in this invention is the loss of deposited material due to the blasting action of the air employed to transmit and project the material particles. It is particularly objectionable in close quarters, such as trenches, molds, forms, etc... In addition to eroding the surface, the released air, in confined space, will setup a series of eddy currents and counter currents in direct opposition to the path of projected materials and under certain adverse conditions depositing becomes practically impossible. This invention seeks to benefit this condition by means to be more fully described hereinafter.

. As to the ballistic properties ofthe particles themselves, it is obvious that these may be altered by mechanical means that disturbs their path of projection and thereby decreases their velocity. This is recognized as another means to the end of this invention.

In one ofmy companion cases, Serial'No.

417,467, filed Dec. 30, 1929, I have shown a nozzle for altering the ballistic'properties of the particles of a mixture by means of an obstruction placed in the path of the flowing particles. p

In another companion case, Serial No. 417,648, filedDec. 31, 1929', I have shown a nozzle arranged to reduce the air pressure at the orifice of the nozzle by means of expansion and deflection.

In still another application, Serial No.

$ .17 ,950, filed J an. 2, 1930, I have disclosed a nozzleprovided with means for partially absorbing the excess kinetic energy of the air transporting medium after it has performed its useful work. There is still another method whereby the excess volume of the air and the kinetic energy of the particles may be appreciably reduced before being deposited upon the surface. This invention purports to deal with means to this end.

, The principle involved in the method which is to be hereinafter disclosed deals with the separation of the air from the particles and the diverting ofthe air before the mass is projected beyond the orifice of the nozzle. The method involved maybe briefly described as a mechanical separation of the particles of the mixture from the air propelling medium and takes advantage of a selective separation of materials of .difierent specific gravities by means of centrifugal force. The device employed turns the column of material and air in a comparatively sharp bend and inso doing, the inertia'of the heavier material particles compels them to seek the outer circumference of the bend while the air being the lighter substance is forced to travel upon the inner or shorter radius, The air still being under compression seeks to expand upon the radius of a transverse section and this fact is taken advantage of to emit the air through an opening or series of openings on the inner circumference of the bend and thus the momentum of the sand particles is also decreased by the change of direction. Therefore, since the particles are of minute form, it.

is clearly obvious that a resistance to the passage of the particles from the nozzle orifice to the surface of deposition is set up in the form of the fixed air which operates to further reduce the speed of each particle.

Another benefit derived by diverting the air resides'in the fact that when cement is deposited in places where a vlimited space is available, such as trenches, forms, etc., the

' operator does not have to contend with the excess flow of air. It is well understood by those versed in this art that in transporting .cementitious mixture through a. conveyor hose, anv initialhead of air is required to overcome the'inertia of the particles and set them in motion,that is'far in excess of the volume and the velocity of the air required to depositrthe particles upon a surface. It is, therefore, recognized that some means .of reducing the volume and the velocity of the air after it has performed its useful work of conveying the particles to the nozzle would reduce air erosionandconsequently would be highly advantageous in cement gun equipment. Accordingly, it is an object of this invention toprovide a means tothis end.

It is evident that the principle of this invention may be combined with the several principles disclosed in my co-pending applications hereinbefore mentioned which combinations will be more fully disclosed in'the fol lowing description. r

The principleinvolved in, this invention may be further utilized as a means of reducing the volume and, consequently, the velocity of the air transporting medium at any point in-the hose conveyingsystem where it is de-' sirable.

The foregoing deals with the principle involved in my invention. Some of the advantages have been set forth andothers will appear in the description when read in conjunction with the, drawings, which Fig. 1 is an elevation partly in section showing somewhat diagrammatically my invention as embodied in-a nozzle, 7

Fig. 2 is anelevation taken on the line 22 of Fig.1; I

,Fig. 3 is an elevation partly in section showing another form of my nozzle; i

, Fig. 4 is aview taken on the line H of Fig. l; I

form which my invention 1, I have shown the modified form of nozzle which illustrates the principle involved in this invention. The nozzle A is formed with a bend which turns the orifice 11 substantially at right angles to the shank 12 of the nozzle. The degree of bend is not to be considered as fixed at 90 but may vary to suit conditions. Upon the short radius of the bend I have formed a single opening.

or a series of openings 13 in any suitable man-v ner. The nozzle A, for purposes of conventionalhandling, is equipped with a handle 14 which may be attached in any suitable 'manner. In practice, the sand and air are conveyed through the conduit. C to the water ring B where it is thoroughly hydrated and from there it passes up the shank12 of the nozzle A substantially in the directions of the arrows 15. The separation of the air from the sand depends upon centrifugal force. It v is obvious that as the air and sand columnis deflected, the; mass of the sand being 'con-fl siderably greater than the mass of the air, thesand will seek the outer circumference of the bendand the air will be correspondingly forced toward the inner circumference. This operation in effect actually separates the sand and the air. In order to take full advantage of this separation, Ihave formed the openings13, as before stated, on the inner circumference of the bend. These openings operate to emit the clear air substantially in the direction as shown by the arrows 16 The sand particles either'by rolling around the outer circumference of the nozzle or by impacting thereagainst v are deflected and are projected through the, orifice 11 onto the working surface. By means of this separation, a large amount of the air volume is extracted from the colunm with the consequence that the velocity of the air is materially re duced, and air erosion minimized. The speed ofthe sand particles is also reduced by imparting a certain amount of their kinetic energy upon contacting with the outer wall of the bend in the nozzle A, and may be further retarded by introducing bafiies, ridges, etc., in their path of travel. It-is evident that as the sand particles leave the orifice ll'they must rely largely upon their own momentum ed; This arrangement, therefore, will be appreciated as providing a means for the purpose of this invention, A nozzle of this type is particularly useful in applying sand upon a surface where the density is not of prime importance and where the space limitations require that the nozzle be used in comparatively close quarters to the surface of the deposition. r

In Fig. 3, I have shown the principle of this invention embodied in combination with the principle as disclosed in my co-pending application, Serial No. 417,467, filed Dec. 30, 1929, wherein I have disclosed means for decreasing the speed of the sand particles by interposing an obstructing element into the path of the sand particles. In this arrangement it is to be understood that the principles of my invention are employed in identically the same manner and that the structure involves a nozzle A mounted upon the conventional water ring B which is supported in the usual manner upon the material conveying conduit C. Air outlets 13 are provided in the manner prescribed on the short radius of the bend in the nozzle A. The only difference between this type of nozzle and the one illustrated and described in Fig. 1 resides in the inclusion of an expanded orifice 17 and an obstructing element D inserted therein and-supported by means of extending vanes 19 which are suitably mounted in the wall of the orifice 17. The element D is designed to set up a disturbance amongst the sand particles and deflect them somewhat upon the lines shown by the arrows 18. It is readily recognized that such a disturbance amongst the sand particles creates a friction which in turn dissipates a large amount of kinetic energy of the particles and that the particles by their reaction against the transverse section of the obstruction perform a large amount of inefi'ective work which further reduces the energy of the particles and, consequently, their speed. This type of nozzle may be operated very successfully where a large volume of material and comparatively low density of deposited product is required.

There may be cases where a nozzle capable of depositing an excessively large volume of material with a very low density arise. For

this purpose a nozzle such as illustrated in Fig. 5 becomes effective. It is apparent that the arrangement shown in Fig. 5 embodies, in conjunction with that arrangement shown in Fig. 3, a further principle such as is de scribed in my co-pending application, Serial No. 417,950, filed J an. 2, 1930. The structure in this instance comprises the nozzle A which embodies the basic principle of this invention, mounted upon the usual water ring B which is in turn supplied by material through the conduit C. The nozzle A is formed with the air outlets 13 which have relation to Fig? 3 d has the obstructing tilement D mounted upon the vanes 19 in'the manner described concerning Fig. 3. This arrangement further embodies the principle of absorbing a certain amount of excess energy of the airpropelling medium prior to emission from the nozzle. For this purpose, passages 20 are provided and are arranged in advance of the obstruction which sets up the disturbance in the sand particles of the stream. The principle involved inthis I arrangement may be briefly stated as follows: The sand and air column having arsorbed by causing it todraw the dead air surrounding the nozzle into the nozzle through the passages 20. It is evident that by setting up movement in the dead air stirg0 rounding the nozzle, a certain amount of the kinetic energy of the live air is absorbed, the consequence of which is to reduce the velocityof the total air which manifestly minimizes air erosion and reduces the speedlof the projected particles and consequentlydecreases the rebound of the particles. It thus becomes apparent that a nozzle is provlded characterized by operating upon several rived at the orifice 21ofthe nozzle A passes into the expanding orifice 17. The excess energy of the propelling air is partially ab principles, all of which tend to reduce the velocity of theparticles and some of which reduce the Velocity and the volume of the air transporting medium. This nozzle, as before stated, is peculiarly adapted for the deposition of a large volume of material of a comparatively low density.

In Fig. 6, I have shown a special adaptation of the principle of this invention. The device embodied in this application comprises a tubular section generally designated at F. 'The tubular section F is formedin substantially an S formation and is provlded with a series of openings 23 arranged on the short radius of the bends in the tube. The openings 23 function in the identical/ manner described with'respect to the principle involved and as illustrated in Fig. 1. In order that the element F may be interposed at will in a material conveying conduit, it is equipped at each end with conventional means 24 for joining a screw-threaded eleinent thereto. This particular structure may be utilized at convenient intervals throughout the material conveying hose, if found desirable, or it may be placed in advance of and closely adjacent to the water ring. 2

to reduce the air volume in the conduit. This 530 feature may be found particularly advanltageous where Work is required to be done in V close quarters and an excess of an would be H objectionable. It is also evident that in place of one of the screw-threaded connections 24, a conventional ,nozzle may be formed and the device mounted upon a water ring inthe 7 usual way of mounting a nozzle. p A further adaptation of the principle of this invention is shown in Fig. 7 Here I have illustrated anozzle A having a sharp bend therein and provided with a slotted opening 25 on the short radius of the bend. Under this arrangement, the orifice 26 may 15 be elongated either vertically or horizontally.

lizing my invention, I am aware that other While I have shown several ways of utimeans may be employed to obtain the benefits sought. I, therefore, intend-that this invention shall include the principles involved and I all means of utilizing the same as and for the purpose described.

, I claim as my invention:

1. In a nozzle for projecting material particles by means of a compressed agent: means for separating and diverting from the particles of material a portion of said compressed I agent prior to passage through the orifice of V i the nozzle, said means including a nozzle having a bend therein; and an air outlet in the wall of the nozzle corresponding to the short radius of the bend.

2. Anozzle of the character described comy I prising: a casinghaving a bend therein; and an outlet through the wall of the casing corresponding to the short radius of the bend.

3. A. nozzle ofthe character described comprising: a casing adapted to be mounted on .a material conveying conduit, said casing' embodying a tubular body terminating in an orifice and having an abrupt bend therein with outlets through the wall of the casing Igori'iesponding to the short radius of the en a 1 4:. A nozzle of the character described comprising a casing adapted to be mounted on a material conveying conduit, said casing embodying a tubular body terminating in an orifice and having an abrupt bend therein y with outlets through the wall of the casing corresponding to the short radius of the bend and a material obstructing element arranged in said orifice.

5. In combination with an air operated material conveying condult and a water ring:

a nozzle comprising a tubular body adapted to be mounted on said water ring, said body terminating in an orifice of larger diameter than the main body portion, and having an abrupt bend therein; air outlets in the wall of the body correspoding to the short radius of the bend; and a material obstructing body arranged in said orifice.

6. In combination with an air operated material conveying conduit means for separatlng and diverting from the particles of mate-

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