US2344703A

US2344703A - Apparatus for handling materials

Info

Publication number: US2344703A
Application number: US357120A
Authority: US
Inventors: Maxwell F Kemper
Original assignee: Individual
Current assignee: Individual
Priority date: 1940-09-17
Filing date: 1940-09-17
Publication date: 1944-03-21
Anticipated expiration: 1961-03-21

Description

March 21, 1944. F, KEMPER APPARATUS FOR HANDLING MATERIALS Filed Sept. 17, 1940 Patented Mar. 21, 1944 7 UNITED STATES PATENT OFFICE APPARATUS FOR HANDLING MATERIALS Maxwell F. Kemper, Los Angeles, Calif. Application September 17, 1940, Serial No. 357,120

10 Claims- (Cl. 302-57) My invention relates principally to the pneumatic conveying of discrete solid particles in a wet, dry or semi-fluid state, such as grain, sand, mixed materials of varying sizes, cement or mixed concrete in its wet semi-fluid or plastic state ready for placing in final position.

The object of the invention is to provide means for improving pneumatic conveyance of such materials so as to prevent segregation or classification of mixed materials into different types or sizes during the blowing operation, to prevent discharge in slugs or wads separated by air pockets, and to reduce the volume of air required with consequent reduction in pressure equipment cost, and power consumption.

The invention resides primarily in an air-control valve for controlling the supply of air into a discharge throat at the lower end of a materials supply hopper, which valve opens by movement into or toward one end of said throat and has a pointed end directed toward said throat so as to penetrate readily into wet mixed concrete or other loose solid particles. The hopper is a pressure chamber sealed at its top, and the materials are discharged from the opposite end of said throat. The invention resides also in the particular shape of said valve which approximates turnip-shape whereby to distribute the high pressure air evenly behind or through the cement bodies, or other bodies of solid particles, which are to be picked up by the air stream and conveyed. The rear portion of the valve is generally a part of a sphere being approximately or somewhat more than a half-sphere, while the valve point is reversely curved to elongate the valve beyond the normal limits of the sphere, to yield a streamlined structure producing streamlined movement of the air. The invention also resides in an elongated horizontal throat at the bottom or discharge end of said hopper into which throat the hopper feeds, in combination with a compression chamber in which said valve works, whose inner walls approach in shape a parabola having its axis alined with the axis of the throat. The invention also includes the use of a conical bot-.

tom for the hopper, said bottom feeding to said throat, its conical shape insuring proper gravity feed of the materials to the throat.

In the pneumatic conveying of particles of mixed sizes, and of wet mixed concrete in particular,1 have found that with the ordinary types of apparatus the concrete is picked up in slugs with air pockets therebetween containing lighter materials separating the slugs, with the result that the concrete is conveyed in slugs and dis-- charged "shot-gun fashion. This operation causes a segregation of the larger particles or aggregate from the smaller sand particles, water and cement. This classifying action, especially when thin walls are being formed, shows coarse rock pocket-s interspersed in the main body of finer cement materials when the forms are removed. Such unevenness is objectionable from all standpoints, such as strength, penetration and appearance. These objections are overcome by the present arrangement of discharge throat, compression chamber receiving the valve, and the reversely curved pointed valve.

r In the accompanying drawing wherein the invention is illustrated in certain embodiments,

I Fig. '1 is a vertical section showing the discharge throat and valve as employed on the lower end of the conical bottom of a materials hopper or pressure chamber;

Fig. 2 is a cross section from line 2-2 of Fig. 1.

Fig. 3 is a cross sectional detail taken on line 33 of Fig. 1.

The lower end H of the conical bottom of a sealed pressure chamber adapted to be filled with mixed wet concrete or other materials comprising solid particles supplied through a scalable gate at the top, is shown as being securely joined to an elongated horizontal throat ill. The top of throat I0 is flared out in conical formation at I to join the hopper bottom I-I, this throat top F being circular'in cross section at the cross-section line 22 as shown in Fig. 2. Both extreme ends of throat l0 beyond the inlet, portions of the flared section F are circular in cross section.

' Thus, the circular discharge end D of throat It) may be joined'to a cylindrical discharge pipe P and the circular air inlet end A of throat l0 may be joined to a circular compression chamber member C which'receives and provides a seat for the air-control valve V. i

, The compression chamber 0 is a chamber which first receives high pressure air admitted by valve V. The curves of its inner walls ll closely approximate parabolas. While this form is preferred, elliptical curves may be used with a fair degree of success; less satisfactory curves would be 'hyperbolas, semi-circles and the like 'to produce other forms of concave chambers. The axis of these walls alines with the axis of the throat l0, and the circle at the extreme outer edge coincides with that of the adjacent inner wall of throat Ill. The rear of these walls ll adjacent the apex is formed into a seat for the spherical rear portionl-2 of the valve-V.

The rear and middle portions of the valve V are generally spherical in shape except as the rear portion is flared away to join the valve stem I3; or it may be said that the rear portion constitutes a half-sphere or somewhat more than a halfsphere except for the connection with valve stem I3. From the middle portion the valve is reversely curved at M and extends forward to a point or tip [5 which may be blunt at its. extreme end.

This curvature is such that it makes the length of the entire valve, exclusive of the valve stem, slightly less than or approximately twice the diameter of the full sphere generally represented by the rear portion 12 of the valve. This contour is stream-line and may be generally termed of turnip-shape.

The pointed forward end ll: of the valve V facilitates its forward movement into a body of soft concrete or other body of solid particles feeding down from the hopper H. When the valve V is moved forward from its seat on compression chamber member C, it admits high pressure air to said chamber C and throat In from a chamber in a valve carrier K supplied by an air line 22. Carrier K is secured to member C by bolts 23, and valve V is positioned by the mounting of stem IS in a boss 24 projecting into chamber 20, the valve stem being packed in said carrier and boss at 2-5.

Valve V is normally held closed by a sufi'iciently heavy spring 28 around valve stem l3. It is openedthrough a lever 28 f-ulcrumed at 29 on a positioning link 30 pivoted at 3! on the body of carrier K, lever 28 being pivotally connected at 32 with the outer end of said valve stem [3. Movement of the lever handle 28 to the left as desired opens valve V by movement to the right. In operating the device, the hopper H will have been filled with concrete or other substance to be pneumatically conveyed and will have had its filling opening at the top sealed substantially air tight. The tapered or conical bottom. H of the hopper and the correspondingly flared or tapered section F will insure a sufficiently even feedof the materials into the throat Ill which is fully cylindrical at its air inlet end A and at its discharge end D, and is approximately semi-cylindrical in the lower, half of its middle portion, the sides of thesection F above said middleportion sloping uniformly down to join the upper portion of the semi-cylindrical portion as seen in Figs. 2 and 3. Forward of the middle portion of throat I0, the sidewalls are rounded away as shown at R to offer the least resistance to the down flow of the concrete and to the discharge of the same from the dis-charge end D-of throat l0 into discharge pipe P.

At the rear or air inlet end A of throat I 0, the, cylindrical contour ofthe end A is maintained as much as possible so that the main bore tends to extend straight through alongthe axis of throat II) to cause the air stream to be directed toward the discharge D. Thus, where the sloping walls of section F join the cylin-' drical section A of throat ID a sharp sloping shoulder results as indicated at S.

By virtue of the parti-spherical contour of the rear portion of valve V together with the reversely curved portion I4 of the point l5 thereof, and the generally parabolic form of the comression chamber walls II, the air stream admitted past valve V is uniformly distributed over the circular cross-sectional area of throat Ii) behind the descending body of concrete, whence it uniformly mixes with the concrete and feeds it forward without apparent segregation or classification of particles of different sizes and condition. This stream-lined air flow, together with the gravity feed from the conical hopper, causes a continuous uniform conveying of the concrete through an elongated extension of discharge pipe P to the point of deposit, and results in a uniform deposit without rock pockets and segregated fine material, water and the like. At the same time, the air volume required has been found to be reduced by as much as The term turnip-shape is here used to indicate the stream-lined or spheroidal contour of the valve V with its elongated reversely-curved pointed extension 15, and the term parabolic" refers to the form of concavity shown and described as the shape of wall ll of the compression chamber C. Modifications to produce the same or like results will occur to those skilled in the art.

I claim:

1. Apparatus for the pneumatic conveying of loose particles comprising a' horizontal throat, means to feed particles into said throat laterally thereof, discharge means in line with aid throat to conduct particles away from said throat, a chamber aligned with said throat and having a valve seat at its end remote from said throat, a pointed valve Within said chamber adapted to seat on said seat and movable axially of said chamber, said valve having a projected area within the chamber normal to the chamber axis greater than the area of the opening in the valve seat, and means for supplying air past said valve. 1

2. Apparatus for pneumatically conveying loose materials comprising an elongated throat having an air receiving end, a discharge end and a materials supply inlet, a concavity alined with the axisof said throatand ends and having a valve seat whose axis alines with said axis, a pointed spheroidal valve alined with said axis and movable along saidaxis from said seat toward said throat, and an air supply to said valve seat to supply air past said valve for discharging'said materials through said discharge end.

3. Apparatus according to claim 2 wherein said I concavity approximates parabolic shape. 50

4. Apparatus according to claim 1 wherein the rear portion of the valve adjacent said seat ispar-ti-spherical and the forward portion of the valve is reversely curved and extended to a point directed toward said throat.

5. Apparatusaccording to claim 1 wherein the rear portion or" the valve adjacent said seat is parti-spherical and the forward portion of the valve is reversely curved and extended to a point along said axis, and the chamber is concave with a curvature which approximates a parabola.

' 6. A; pneumatic feed comprising a discharge throat, a curved wall chamber co-axial-ly alined and communicating with said throat and having 7 a valve seat and a co-axiall'y alined turnipshaped valve seating on the low pressure side of said valve seat'and pointed into said throat" to distribute air evenly thereto.

7. Apparatus for the pneumatic conveying of loose particles comprising a threat; means to feed particles into said throat; discharge means to conduct particles away from said throat; a

.chamber in communication with said throat; an opening in said chamber for admitting air to said chamber; and a body within said chamber having a projected area normal to the axis; of

said opening greater than the area of the opening; said body being movable toward and away from said opening to thereby control the flow of air'into said chamber.

8. Apparatus for the pneumatic conveying of an aggregate of loose particles of different sizes and weights, comprising; means forming a throat; means to feed said aggregate laterally into said throat; discharge means connected to one end of said throat to conduct the aggregate away from the throat; a chamber communicating with the other end of said throat; an opening in said chamber for admitting air to the chamher, the walls of said chamber diverging in a direction away from said opening and toward the throat; and a body within said chamber, the surface of said body diverging from the walls of the chamber and toward the throat, the walls of said chamber and the surface of said body cooperating to define a passage surrounding said body gradually increasing in cross section from said Opening toward said throat, whereby air flowing through said passage is caused to impinge upon that surface of the body of aggregate facing said passage with a substantially uniform velocity, to move said aggregate without causing segregation of particles of different sizes and weights in the aggregate.

9. A valve for the pneumatic conveying of loose particles comprising a chamber having an opening at one end thereof for the admission of air, the walls of said chamber being gradually divergent from said opening, a body within said chamber having a projected area normal to the axis of said opening larger than the area of said opening, said body being of a generall spheroidal shape, the walls of the chamber and the surface of said body defining an annular passage of gradually increasing cross section.

10. Apparatus for the pneumatic conveying of an aggregate of loose particle of different sizes and weights, comprising; means forming a throat; means to feed said aggregate laterally into said throat; discharge means communicating with one end of said throat to conduct the aggregate away from said throat; conduit means communicating with the other end of the throat; a member in said conduit having a surface di-, verging from the wall of the conduit toward the throat, said member and said conduit cooperating to form a passage gradually increasing in cross section in the direction of air flow therethrough, said passage being positioned adjacent said throat and causing the air passing therethrough to impinge upon the surface of the body of aggregate between the discharge end of said passage and said throat with a substantially uniform velocity, to move said aggregate without causing the segregation of particles of different sizes and weights in the aggregate.

M. F. KEMPER.