US2001661A - Concrete pumping system - Google Patents

Description

May 14, 1935. c. F. BALL CONCRETE PUMPING SYSTEM Filed April 6, 1935 0 VIII/14%? VIJVIIAr/ll/ Patented May 14, 1935 I UNITED STATES PATENT OFFICE 2,001,661 CONCRETE PUIWPING SYSTEM Charles F. Ball, Milwaukee, Wis., asslgnor to Chain Belt Company, Milwaukee, Wla, a corporation of Wisconsin Application April 6 ,1933, Serial No. 664,827 3 Claims. (or. 103-224) This invention relates to pumping systems, and ing devices located in the usual position on or immore particularly to one including a. recently demediately adjacent the pump, the back pressure veloped type of pressure pump especially adapted set up by such damping devices is sufilcient to for handling concrete and plastic mixtures having force portions of the mixture back through e 5 characteristics similar thereto, and has for its valves while thus open, resulting in what istermed 5 principal object to improve the operation and black-slip and lowering the efficiency of the efliciency of such systems. system. In order that the precise nature of the inven- On the other hand, I have found that if the tion maybe clearly understood, it may be said pulsation damping device be 50 located t that the pressure pumps above referred to are communicate with the discharge line atadistance 10 usually, although not necessarily, single cylinder of ay from 5 t0 100 feet from the D pmachines having single acting pistons, i. e. pisp ndent p t Consistency of the mixture tons which suck the plastic mixture into the cyling handled and other factors-the inertia of the inder upon one stroke and force it therefrom up n Portion of the mixture in the Conduit between the 1 the succeeding stroke. Because of the size of dampi g device a d t e pu together w the certain of the constituents of the commonly used friction between the mixture and the Walls of the concrete mixtures-the large aggregate may range conduit, will be sufiicient to overcome the back from one quarter inch up to two and one-half p e Set up by the damping device and p or three inches ingreatest diimension-the valves t reverse m v of the m u r u of these pumps are not designed to seat tightly so the Valves during the intervals WheI1 they are 20 as to completely close off the passages controlled Simultaneously fully nearly fully Op thereby, but are moved in proper seque ce from The invention therefore resides specifically in their fully open positions to positions in which l i the i dome r h r pul ti n ampin they partially restrict but do not fully close their d v ce a a Point in the discharge conduit respective passages, advantage being taken of the eiehtly removed from the p that the inertia 25 peculiar packing 0r stowing property of such and friction of that portion of the mixture lying mixtures at such restrictions to substantially comwithin the conduit between the pump and the pletely prevent movement of the mixture in a didampin device s great enough to resist the b rection opposite to that in which it, is being pressure exerted by the lattertothe extent necespumped. sary to prevent the objectionable back-slip of 30 These pumps usually operate at from 40 t 50 the. mixture through the simultaneously open pressure strokes per minute, there of course being a v all as Will be more fully hereinafter an equal number of suction strokes during which scribed and part c y Pointed Out in the -D- the outlet valve is in its most restricting position pended claims.

and the mixture in the discharge conduit beyond Referring to the accompanying drawing, form- 35 said valve is not being pushed forwardly. This ing a part of this specification, in which like refresults in an intermittent forward movement of erence characters designate like parts in all the the mixture in the discharge pipe, and a pulsatviews:-

ing discharge therefrom. Under many conditions Figure l is a more or less diagrammatic side such pulsating discharge is objectionable, and it elevational view ofa concrete pump of the type 40 has been proposed to smooth out and substanabove mentioned, a discharge conduit therefore, tially eliminate the pulsations-through the use of and a pulsation damping device in the form of air chambers or other pulsation damping devices, an air dome communicating therewith and 10- as is common practice in liquid pumps. cated in accordance'with the present invention:

Notwithstanding the fact that the valves of Fig. 2 is an enlarged fragmentary sectional 45 these pumps are substantially simultaneously acview through the inlet and outlet valves of the tuated-usually by cams to insure positive and pump illustrated in Fig. 1, showing the positions relatively rapid movement from one position to they occupy during the pressure stroke of the the otherthere is a. certain interval during each piston;

valve movement when both valves may be com- Fig. 3 is a view similar to Fig. 2, but illustrating b0 pletely or nearly completely open, and the length the valves in the course of their movements at of this interval may in some instance be increased the end of the pressure stroke of the piston, and if one of the valves has a lead over the other. showing how they may simultaneously occupy Because of this condition, it has been found that nearly fully open positions; and

with the use of air domes or other pulsation damp- Fig. 4 is a view similar to Fig. 2, of a somewhat b5 modiiiodformofpumminwhichasingleval ve controls both the inlet and the outlet passages.

In the said drawing, Ill indicates generally a concretepumphavingacylinder ll providedwith aninletpassage l2 andanoutletpassage II. The inlet passage i2 communicates with a valve housing it inwhich is mounted a plug member II, constituting the inlet valve, and which is provided with a passage ll adapted in the open position of the valve (indicated in broken lines in Fig. 2) to aline with the passages ll of the valve housing ll. The valve plug II is arrangedto be oscillated from its restrictive full-line position illustrated in Fig. 2 to its open broken-line position and back again by means of a valve arm II, a connecting rod assembly ll, anda rocker arm 20, which is actuated by suitable cams within a housing 2|. A feed hopper 22 surmounts the valve housing I4 and receives the plastic concrete from any appropriate mixer.

In similar manner the outlet passage l3 communicates with a'valve housing 25 in which is mounted the outlet valve plug 20, having the passage 21 arranged to aline with the passages I. of the housing 25, and to be moved back and forth between its fulland broken-line positions, illustrated in Fig. 2, by an arm 2!, connecting rod ll,

and a rocker arm and cams located on the far side of the machine. The discharge pipe or con-' duit II is connected to the outlet valve housing 25, and at a point suillciently removed from the pump may be provided with a'fitting 32, upon which may be mounted the air dome or other pulsation damping device I3.

During the pressure stroke of the pump piston II, the valves l6 and 28 occupy the positions shown in Fig. 2, with the inlet valve II in its most restrictive position, and the outlet valve 26 in its fully open position. As the piston 34 reaches the end of its pressure stroke, as indicated in Fig. 3, the cams actuate the respective rocker arms such as 28, the'connecting rods I9 and 30, and the valve arms II and 29, to move the valve plugs II and 26 in a clockwise direction from the full-line positions of Fig. 2 to the broken line positions shown therein. At some time during this operation the valves may occupy substantially the positions illustrated in Fig. 3, in which it will be observed that neither valve imposes much restriction in the passages controlled by it; and it is during the interval that the valves are approaching and leaving these positions that back-slip" may occur if the pulsation damper be located in its usual place on or immediately adjacent the pump. On the other hand, if it be located a suitable distance from the pump, as indicated in Fig. l, the inertia of the mixture within that portion of the conduit 3| between the-outlet valve 26 and fitting 32 will be sufllcient to resist the pressure built up in the air dome 33, and which would tend to force the mixture back toward the pump on the suction stroke of the piston.

Obviously, the same condition permitting of "back-slip will be present in the modified type of pump illustrated in Fig. 4, wherein a single valve 35 controls both the inlet passage l2 and the outlet passage l3, since as the said valve moves from the full line position to the broken line position shown therein,and vice versa, the two passages may be simultaneously open a sufficient time to allow the objectionable backward movement of the material being pumped. The present invention is therefore of value in connection with this form of pump.

As above stated, the exact distance the damper is located from, the pump may, vary, depending upon the character of the mixture being handled; however, I have found that distances ranging from 25 to 100 feet give satisfactory results with all concrete mixtures now in common use when pumping through a five inch discharge line.

It is obvious therefore that those skilled in the art may vary the precise arrangement of the various instrumentalities without departing from the spirit of the invention, and it is not wished to be limited to the details of the above disclosure. except as may be required by the claims.

What is claimed is:-

, 1. The combination with a pump for concrete and similar plastic materials having valve controlled inlet and outlet passages which at certain times in the operation of the pump may be simultaneously open, and a pulsation damping device, of longitudinally extended connections between said pump and device arranged to contain a quantity of the material being pumped sufiicient that the inertia thereof and the friction between said material and the walls of said connections may over-come the back pressure exerted by said damping device and prevent backslip of said material in said passages when they are simultaneously open.

2. A pumping system for concrete and plastic materials having characteristics similar thereto, comprising a pump having valve controlled inlet and outlet passages which at certain times in the operation of the pump may be simultaneously open an amount sufiicient to permit of the plastic material flowing backward therethrough; a discharge conduit leading from said pump; and a pulsation damping device communicating with said conduit at a distance from said pump sumcient that the inertia and friction of the plastic material in said conduit between" the pump and the damping device may resist the back pressure exerted by the lattter to the extent necessary to prevent back-slip of the material through said passages when they are simultaneously open.

3. In a pumping system for concrete and plastic materials having characteristics similar thereto, a pump having valve controlled passages which at certain times in the operation of the pump may be simultaneously open; a discharge conduit leading from said pump; and a pulsation damping device communicating with said conduit at a distance of at least twenty five feet from said pump, whereby the inertia and friction of the mixture in said conduit between the pump and the damping device may overcome the back pressure set up by the latter and prevent back-slip of the mixture through said pump passages when they are simultaneously open.

CHARLES F. BALL.

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