US3889713A

US3889713A - Reciprocating valve for double piston concrete pump

Info

Publication number: US3889713A
Authority: US
Inventors: Horst Bender
Original assignee: Wibau GmbH
Current assignee: Wibau GmbH
Priority date: 1972-07-20
Filing date: 1973-07-13
Publication date: 1975-06-17
Anticipated expiration: 1992-06-17
Also published as: GB1428289A; FR2194240A5; DE2235586A1; IT991963B

Abstract

The present valving apparatus is especially adapted for use in conduits through which construction mixtures, such as concrete mixtures, flow. The valving apparatus is constructed for cooperation with a pump having two pistons in two respective pump cylinders. For this purpose, there are provided a cylindrical valve housing having first ports connected to said pump, second ports connected to conveying conduit means, and third ports connected to supply means, as well as a three member two position valve plug movable back and forth in said valve housing. The valve plug has a central member with a substantially straight passage way and, adjacent to said central member, two end members with curved passage ways, whereby, depending on the position of the valve plug, one of the pump cylinders is connected to said conveying conduit means while the other pump cylinder is connected to the supply means or vice versa.

Description

111 3,889,713 1 June 17, 1975 United States Patent [191 Bender 1 1 RECIPROCATINC VALVE FOR DOUBLE PISTON CONCRETE PUMP FOREIGN PATENTS 0R APPLlCATIONS Horst Bender, Linto rf, Germany WIBAU (Westdeutsche Industrie-und [75] Inventor:

[73] Assignee:

Primary Examiner-William Cline Strassenbaumaschinen-Gesellschaft Attorney, Agent, or FirrizWolfgang G. Fasse; Willard m.b.H.), Rothenbergen, Germany W. Roberts July 13, 1973 221 Filed:

[57] ABSTRACT The present valving apparatus is especially adapted for use in conduits through which construction mixtures, such as concrete mixtures, flow. The valving apparatus ,is constructed for cooperation with a pump having two [21] Appl. No.: 379,195

[30] Foreign Application Priority Data July 20, 1972 Germany............................ 2235586 pistons in two respective pump cylinders. For this purose, there are provided a cylindrical valve housing g first ports connected to said pump, second orts connected to conveying conduit means, and third ports connected to supply means, as well as a .m V a PhD. 76 8 8 mmlww 711 ll 1 65 4 2 6 2.16 G 8 9 76 W ZHM 06 v 6 9 /7 0 7 50 3.029 1W 1 rm oo n3 ma ""13 MHZ nm n6 mmCoo m mm "85 ""82 L TI CGM7 a 3 SL 0 .l U.mF 1 2 1.1 218 555 three member two position valve plug movable back and forth in said valve housing. The valve plug has a References Cited UNITED STATES PATENTS central member with a substantially straight passage way and, adjacent to said central member, two end members with curved passage ways, whereby, depending on the position of the valve plug, one of the pump 2,875,782 3/1959 3,158,901 12/1964 Westoverm.

nduit cylinders is connected to said conveying co Schumann dto Herion et al... 3/1972 Reinert...............................

means while the other pump cylinder is connecte 17/900 the supply means or vice versa. 3,682,575 8/1972 Guddal et a1. 417/517 3,749,525

7/1973 Hooper et 417/900 2 Claims, 3 Drawing Figures PATENTEIJJUN 17 I975 153,8 8 9,713

SHEET SECTION A-I-B FIG. 2

SECTION1 c +0 RECIPROCATING VALVE FOR DOUBLE PISTON CONCRETE PUMP BACKGROUND OF THE INVENTION The present invention relates to a valving apparatus for interconnecting a double piston pump having two cylinders with conveying conduit means and with sup ply means, especially for conveying construction mixtures such as concrete mixtures or the like.

The conventional valving mechanisms for so called concrete double piston pumps usually comprise flat slide means for closing and opening the pump cylinders. Preferably, two flat slides are employed, each of which has its own guide means and which are arranged at a 90 displacement relative to each other. The guide means are arranged in such a manner that the slides may cooperate with the suction and pressure side of the mixture passing conduits. In this kind of arrangement, and assuming the normal operational position of the pump, the vertically aligned slide is arranged for cooperation with the working cylinders of the pump whereas the horizontally arranged slide cooperates with the supply container for the mixture to be conveyed. Stated differently, of the four possible slide positions, two slide positions have to be adjusted simultaneously in such a manner that a pressure passage and a suction passage is provided through the guide and the slide.

It has been found that the above conventional arrangement and many modifications thereof all have the common disadvantage that flat slide members pose, on the one hand a substantial sealing problem while on the other hand, these flat slides are subject to a high wear and tear, especially due to the necessary alternating adjustment of two passage positions each and two closing or blocking positions each. The high wear and tear of conventional slide valving mechanisms is especially serious because it calls for a frequent replacement of the mostly metallic slide plates which means that not only the plates but also the respective guide means must be replaced because the guide means are, of course, also subject to said wear and tear.

The actual useful life of the pump is substantially reduced due to the above mentioned relatively high wear and tear of the slide means which is rather higher than the wear and tear of the remaining pump elements. As a result, it is not practical to overhaul the entire pump and all its parts at uniform time intervals because the maintenance or overhaul work must be geared to the weakest link in the arrangement, namely the slide valving mechanism. On the other hand, a random overhaul of the individual pump elements is respectively subject to down times, which may be rather substantial in their accumulation.

A further drawback of prior art arrangements is seen in that the passage ways on the suction side as well as on the pressure side are constructed in such a manner that a substantial pressure loss cannot be avoided. As a result, the consistency of the material to be conveyed must be maintained within narrow limits. In addition, the conveying distance as well as the conveying head or lift are substantially reduced due to said pressure loss.

OBJECTS OF THE INVENTION In view of the foregoing, it is the aim of the invention to achieve the following objects singly or in combination:

to remove the above outlined disadvantages of the prior art, more specifically, to provide a valving mechanism which may be efficiently used in connection with the conveying of rough materials, for example, concrete mixtures in connection with a double piston cylinder pump for the alternating supply of material to one of the pump cylinders and the discharge of material from the other pump cylinder or vice versa;

to provide a valving mechanism for the here described enviroment which is constructed so as to substantially reduce the friction wear and tear to the extent that overhaul and maintenance work may be practically limited to be performed at uniform time intervals;

to provide a valving mechanism which avoids the pressure drop along its passage ways and thus assures a more efficient conveying distance as well as a better lift;

to construct and arrange the several members of the valving mechanism in such a manner that the travel or displacement distance of the valve closure member is substantially reduced, especially in order to thereby also reduce the wear and tear;

to construct the elements of the valving mechanism and to arrange these elements relative to each other in such a manner that a simple contruction is achieved whereby the maintenance and replacement of parts is made easier and simpler; and

to construct the passage ways of the valve closure member as replaceable inserts of high wear resistan. material.

SUMMARY OF THE INVENTION:

According to the invention there is provided a valving apparatus having a cylindrical valve housing which is preferably arranged to extend with its longitudinal axis at an angle of about relative to the axis of the work cylinders of the above mentioned pump. The valve housing is provided with two suction or inlet ports for connecting the housing to a supply container. The housing is further provided with two outlet ports for connecting the valve housing with a conveyor conduit means and two additional ports for connection to the working cylinders of the pump. Three valve plugs or valve sections forming preferably an integral piston type of valve plug are arranged in series with each other, so as to be compatible with the function of suc' tion, pressure, and suction in that order. The valve plug sections or members forming the ends of the integral valve plug are arranged so that one of these end members is closed by the valve housing while the other end member provides a passage way for the material to be conveyed from the supply means to the cylinder of the pump which at that instance acts as a suction means and vice versa. The plug member arranged intermediate the two end members provides a passage way for the flow of the material to be conveyed from the cylinde of the pump which at that instance acts as a pressure cylinder for transferring the material to a conveying conduit. The valve plug is movable back and forth between two opposite end positions in response to the respective movement of the pump pistons.

Preferably for this purpose, the valve plug is connected to means for moving the valve plug back and forth, for example, by means of a plunger rod connected to one or both ends of the valve plug.

BRIEF FIGURE DESCRIPTION:

In order that the invention may be clearly understood, it will now be described, by way of example, with reference to the accompanying drawings, wherein:

FIG. 1 is a longitudinal sectional view through a valving apparatus according to the invention;

FIG. 2 is a sectional view along the sectional line A,B of FIG. 1; and

FIG. 3 is a sectional view along the section line CD of FIG. 1.

DETAILED DESCRIPTION OF AN EXAMPLE EMBODIMENT:

FIG. 1 illustrates a longitudinal sectional view through a valving apparatus according to the invention, whereby the valve housing 1 has a cylindrical shape and is provided with port means for the connection to a double piston pump, to a conveying conduit and to a supply container. A valve plug 7 constructed as a piston type three member plug controls the action of the valve as will be described in more detail below. The flow of the material through the valve, for example, a concrete mix, is shown by the dashed line arrows.

The valve housing 1 is closed by cover members 2. A stuffing box and guide bushing 3 is connected to one or both of the cover members 2. Each guide bushing receives a plunger rod 4 which is connected to the valve plug 7 and which is actuated in response to the operation of the pump, more specifically, in response to the movement of the work pistons of the pump. When these pistons reach their respective end positions, the valve plug is actuated in one or the other direction through well known linkage means connected between the pump and the plunger rod or rods 4. Only one plunger rod may also be used.

According to the invention, the valve plug 7 is pro vided with three separate sections or plug members including an end member 5, a second end member and an intermediate member 6. Preferably, these members are constructed to form an integral valve plug.

As mentioned, the valve housing 1 is provided with first port means 8' and 9' for connecting the valve housing to the respective cylinders 8 and 9 of the double piston pump which itself is not shown in detail. The valve housing comprises second port means 10 and 11 for connecting the valve housing to conveying conduit means 20, preferably, with the aid of a Y-conduit member having two

legs

12 and 13 connected to the ports 10 and 11 respectively and an outlet port 16. The valve housing is provided with further port means 14 and 15 which are preferably flanged to a supply container for the material to be conveyed. The container itself is not illustrated.

Referring to FIG. 2, the intermediate plug member 6 forms preferably a straight passage way from the cylinder 8 to the conduit leg 12. Further, the plug is made of synthetic material, for instance a silicon rubber, and the passage way itself is formed by an insert of a high wear resistant material, such as steel. Preferably, the insert 18 is removable to facilitate the maintenance of the valve and to prolong its useful life.

Referring to FIG. 3, the

valve end members

5 or 5 are also made of synthetic material, such as silicon rubber, and again an insert 17 is provided for a passage way through the valve plug. Preferably, the inserts 17 have a bent shape to form a knee as illustrated. Preferably, the ends of the knee include an angle of less than 90, preferably As mentioned, the valve plug 7 is movable back and forth between two end positions and the length of the plug from end to end is correlated to the inner length of the valve housing 1 in such a manner that in each position of the valve plug, one of the two passage ways formed by the end plug members is closed by the valve housing 1 while the other passage way connects the supply container to the respective pump cylinder. In the position shown in FIG. 1, the plug member 5' interconnects the supply container with the suction cylinder 9 of the pump and the passage way through the plug member 5 is closed. When the plug 7 is moved in the direction of the horizontal arrow to its other end position, the situation would be reversed. The central valve plug member 6 interconnects in the position shown the pressure cylinder 8 with the leg 12 of the Y- member. In the other position of the valve plug, the passage way through the central member 6 would be from the cylinder 9 to the leg 13.

A valving apparatus as described above has substantial advantages. The valve housing as well as the valve plug may be easily constructed due to their cylindrical shape whereby precision work may be accomplished due to said shape thus providing a better sealing characteristic than has been accomplished heretofore in connection with flat valve slide members. Furthermore, the direct interconnection between the various ports without the interference of any guide means for a slide greatly improves the flow characteristics so that pressure drops are avoided.

Further, the location of the several ports relative to each other also facilitates achieving smooth flow characteristics.

Another advantage of the invention is seen in the provision that the control plug has three distinct sections or members arranged in series with each other and functioning respectively in the suction passage, in the pressure passage and again in the suction passage in that order. This greatly facilitates the displacement of the plunger as an integral unit and does not interfere with the alternating suction and pressure function of the pump cylinders 8 and 9. Another advantage of the invention is seen in that the length of the control movement of the plug or the plug stroke is substantially reduced, which in turn, it has been found, by itself reduced the wear and tear by about 25 percent. A further reduction of wear and tear has been achieved according to the invention due to the fact that the two outer passage ways have a gently bent shape forming a knee of preferably less than whereas the central passage way is a straight passage way. A knee bent of about 75 has been found to be especially advantageous with regard to reducing wear and tear.

Moreover, it is advantageous to make the passage ways of uniform cross-sectional diameter and to provide the plug members with replaceable inserts whereby the useful life of the entire structure may be substantially increased. On the other hand, the plug members themselves may be made of synthetic material such as silicon rubber which facilitates the insertion and replacement of the inserts which are preferably made of high wear resistant steel or the like.

The above combination of features not only reduces the wear and tear by a reduction of the length of the valve plug stroke but it also improves the flow characteristics and reduces the maintenance time which heretofore has been necessary for the exchange of the valve slides with their respective guide means. Moreover, it is now possible to employ maintenance intervals of uniform duration.

Although the invention has been described with reference to a specific example embodiment, it is to be understood, that it is intended to cover all modifications and equivalents within the scope of the appended claims.

What is claimed is:

1. A valving apparatus for interconnecting a double piston pump having two cylinders with conveying conduit means and with supply means; comprising a cylindrical valve housing having a given length, said housing further having a first pair of aligned ports for connecting said valve housing to said two pump cylinders, 21 second pair of aligned ports for connecting the valve housing to conveying conduit means, and a third pair of aligned ports for connecting the valve housing to said supply means, said ports being aligned at a pair of 2() planes extending transverse of the axis of said housing with each port of each pair of ports being aligned with a separate one of said planes, a piston valve plug mounted solely for axial movement in said cylindrical valve housing, said plug having a central plug section (6) with a straight cylindrical passageway extending diametrically through the valve housing in a direction to interconnect ports of said first and second pair in a common plane, a first outer plug section (5) with a bent cylindrical passageway, and a second outer plug section (5) also with a bent cylindrical passageway, said first and second outer plug sections and said central plug section having together a length corresponding to about three quarters of said given length of the cylindrical valve housing, said first and second outer plug sections (5, 5 extending on each side of said central passageway, each of said first and second bent cylindrical passageways including an angle within the range of about to about so as to extend 2. The valving apparatus according to claim 1, wherein said plug sections from a unitary member made of silicon rubber material, and wherein said passageways comprise highly wear resistant inserts made of steel.

UNITED STATES PATENT oFFIcE QE'HFICATE OF CORRECTION Patent No. 3 713 Dated June 17 1975 lnventorgs) Horst Bender It is certified that error appears in the aboveidentified patent and that said Letters Patent are hereby corrected as shown below:

Column 6, line 16 after "extend" insert:

--in a direction to interconnect ports of said first and third pairs of ports in a common plane, said passageways being axially spaced, whereby in. one

axial position, said central passageway interconnects one port of said first pair with one port of said second pair, while one of said outer bent passageways interconnects the other of said first pair with one of said second pair, and whereby in another axial position said central passageway interconnects the other ports of said first and second pairs, while the other of said outer passageways interconnects said one of said first pair of ports with the other of said third pair of ports, and means operatively connected to said valve plug for axially moving said valve plug in said valve housing so as to be compatible with the function of suction, pressure and suction in that order for each work cycle of the valve.

Signed and Sealed this twenty-sixth Day of August1975 [SEAL] A rtes t:

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner uflarenrs and Trademarks

Claims

1. A valving apparatus for interconnecting a double piston pump having two cylinders with conveying conduit means and with supply means; comprising a cylindrical valve housing having a given length, said housing further having a first pair of aligned ports for connecting said valve housing to said two pump cylinders, a second pair of aligned ports for connecting the valve housing to conveying conduit means, and a third pair of aligned ports for connecting the valve housing to Said supply means, said ports being aligned at a pair of planes extending transverse of the axis of said housing with each port of each pair of ports being aligned with a separate one of said planes, a piston valve plug mounted solely for axial movement in said cylindrical valve housing, said plug having a central plug section (6) with a straight cylindrical passageway extending diametrically through the valve housing in a direction to interconnect ports of said first and second pair in a common plane, a first outer plug section (5) with a bent cylindrical passageway, and a second outer plug section (5'') also with a bent cylindrical passageway, said first and second outer plug sections and said central plug section having together a length corresponding to about three quarters of said given length of the cylindrical valve housing, said first and second outer plug sections (5, 5'') extending on each side of said central passageway, each of said first and second bent cylindrical passageways including an angle within the range of about 75* to about 90* so as to extend

2. The valving apparatus according to claim 1, wherein said plug sections from a unitary member made of silicon rubber material, and wherein said passageways comprise highly wear resistant inserts made of steel.