Abstract:
An apparatus for automatically producing solutions at predetermined dosages is proposed in particular of cleaning water for pressing machines wherein water is used as main fluid and a concentrate to be added to the water. The apparatus has a dosing device which communicates with a mixing container and includes a reciprocating control slide which alternatingly supplies the main fluid which is under pressure to one side of a plunger which thus reciprocates in dependence on the control slide and discharges the main fluid in the mixing container, each side of the plunger being connected to a piston rod which has a piston through which the concentrate is also exactly discharged to the mixing container.

Description:
SUMMARY OF THE INVENTION 
     It is a general object of the invention to overcome the difficulties of the prior art. 
     More particularly, it is an object of the present invention to provide an apparatus for automatically producing solutions at predetermined dosages which allows the mixture of at least the three mediums. 
     Yet another object of the present invention is to provide an apparatus which is not provided with electrical drives. 
     A concomitant object of the present invention is to achieve an apparatus for automatically producing solution at predetermined dosages which is simple in construction, reliable in operation and inexpensive to manufacture nevertheless. 
     In keeping with these objects, and with others which will become apparent hereafter, one feature of the invention resides, briefly stated, in an apparatus comprising a mixing container having an outlet, and a dosing device associated to the mixing container, wherein the dosing device includes a housing having an axis, a control slide reciprocating in an axial direction in the housing under influence of a pressure medium and controlling the supply of the main fluid, and means for discharging the main fluid and the concentrate into the mixing container in a predetermined dosage and simultaneously providing a further predetermined dosage thereof, the discharging and providing means reciprocating under the action of alternate impingement by the main fluid discharged in response to the reciprocating movement of the control slide. 
     According to a further feature of the invention, the discharging and providing means includes a plunger reciprocating in axial direction within a cylinder and having two contact faces alternatively impinged by the main fluid in accordance with the movement of the control slide for discharging the main fluid to the mixing container, wherein the main fluid providing the movement of the plunger remains in the cylinder and is dischargeable when the other side of the plunger is impinged by the main fluid. For providing the dosage of the concentrate, the plunger is connected to one end of at least one piston reciprocating in a cylinder which is in communication with an inlet for the concentrate and an outlet to discharge the concentrate to the mixing container, wherein the piston reciprocates in accordance with the plunger so that upon discharge of main fluid by the plunger, a concentrate is simultaneously dischargeable to the mixing container at a predetermined dosage. 
     The control slide according to the invention includes a piston rod which is guided in a cylinder with a play and whose stroke is limited. The piston rod is further provided at its ends as well as in the center with a piston wherein the cylinder is in communication with the mixing container via two ducts and with the main fluid via a further duct. Depending on the position of the control slide, i.e. of the center piston, one of the two ducts is closed thereby providing a connection for the main fluid which is continuously under pressure to the one side of the plunger so that the plunger is shifted thereby forcing the main fluid within the cylinder to flow through the other of the two ducts into the mixing container. 
     According to a further feature of the invention, each of the pistons located at respective ends of the piston rod communicates with a cylinder space wherein the two cylinder spaces are alternatively impinged by the pressure medium for providing the reciprocating movement of the control slide. In a simple manner each of the cylinder spaces accommodates one portion of a piston rod which is slidable and axially extending. Each piston rod is provided with a groove which is in connection with at least one radially extending bore hole opening in an axially extending channel which leads to the respective cylinder space. It has proven as especially preferable that each groove is alternatively in communication with one of two through holes, wherein one of the through holes being passed by the pressure medium while the other of the through holes is in connection with a pressureless return pipe. 
     According to still another feature of the invention, each of the piston rods facing the respective piston of the control slide provided with a stop member wherein each of the springs has one end resting on the respective stop member while its other end abuts the casing. At least one of the piston rods is further provided at its other end remote to the respective stop member with a retainer projecting from the casing. 
     The advantage of the apparatus according to the invention resides in the fact that the main fluid which is usually water is used as means for moving the plunger and is simultaneously the fluid to be mixed in the mixing container. Furthermore, since the movement of the plunger is obtained through the use of water, the apparatus is explosion-proof. A further advantage is obtained by the development of the mixing container in which three mediums can be mixed. The apparatus is simple in construction and nevertheless allows the mixture of three mediums without external energy in the area of parts pro mille in very exact manner. 
     The novel features which are considered characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     FIG. 1 is a side view of the apparatus according to the invention; 
     FIG. 2 is a top view of the apparatus of FIG. 1; 
     FIG. 3 is a sectional view along line III--III according to FIG. 2; 
     FIG. 4 is a sectional view along line IV--IV according to FIG. 2; and 
     FIG. 5 is a sectional view along line V--V according to FIG. 2. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring firstly to FIG. 1, there is shown a dosing device 1 which is screwed in a not shown manner to a mixing container 2 which is provided with an outlet 3 for the solution to be mixed, for example cleaning water. The solution is then supplied to for example a pressing machine. As can be further seen from FIG. 1, the dosing device is accommodated in a housing 4. 
     Referring now to FIG. 2, it can be seen that the dosing device 1 includes a control slide 5 reciprocating in axial direction. The control slide 5 includes a piston rod 6 whose respective ends and center is provided with a piston 7, 8, 9. Through the provision of such a control slide, two cylinder chambers 10, 11 are provided wherein depending on the position of the control slide 5, i.e. of the piston 8, one of the cylinder chambers 10, 11 is in connection with the main fluid via a duct 12. It is to be noted that the main fluid is continuously under pressure. When the control slide has occupied the position as shown in FIG. 2, the piston 9 is closing a duct 13 which is connected to the mixing container 2 while the duct 14 which is also connected to the mixing container is open, the purpose thereof being described hereinbelow. 
     The stroke of the control slide 5 is limited in axial direction by spaced locking rings 17, 18 which are alternatingly abutted by the respective pistons 7 and 9 so that intermediate spaces 15, 16 are obtained. Two further cylinder spaces 19, 20 are arranged in axial direction subsequent to the intermediate spaces 15, 16 in which cylinder spaces 19, 20 piston rods 27, 28 respectively protrude. The ends of the piston rods 27, 28 which face each other are each provided with a stop member 21, 22. In each of the cylinder spaces 19, 20, a pressure spring 23, 24 is arranged abutting the respective stop member 21, 22 with one end thereof while the other end of the spring is resting on the respective wall 25, 26 of the cylinder space. Each of the piston rods 27, 28 is guided in a casing 29, 30 in a sealing manner wherein for example, the casing 30 is fixedly connected to the housing 4 (not shown). 
     The casing 29 as well as the casing 30 is provided with two through holes 31, 32; 33, 34. The through holes 32 and 33 are connected with a return pipe and the through holes 31 and 34 are connected to a source of pressure medium. 
     In the position as illustrated in FIG. 2, the through hole 34 is covered by the piston rod 28, while the through hole 33 is in connection with a groove 35 which is cut into the piston rod 28. The groove 35 is in communication with the intermediate space 16 via radially extending bore holes 36 and an axially extending bore hole 37. The piston rod 27 is equally provided. As shown in FIG. 2, the borehole 32 is closed by the piston rod 27 while the through hole 31 which is connected to the pressure medium source is in connection with a groove 38a. The groove 38a is connected to the intermediate space 15 via radial bore holes 36 and an axially extending bore hole 37. 
     Each of the piston rods 27, 28 is provided at its end remote to the stop member 21, 22 with a retainer 39, 40 wherein the retainers 39, 40 project beyond the casing 29, 30 and cooperate with respective reverse members 41, 42 as can also be seen from FIG. 3. Each of the reverse members 41, 42 surrounds a respective sleeve 43, 44 which is rotatably mounted in respective housings 45,46 with one end thereof. The mounting of the sleeves 43, 44 is in such a manner that no axial movement can occur. The housings 45, 46 are screwed to the casing 4 in a sealing manner and are each provided with a projection 47, 48 facing each other. A pipe 49 surrounds both projections 47, 48 so that a cylinder space 50 is provided in which a plunger 51 is arranged. On both sides of the plunger 51, axially extending piston rods 52, 53 are mounted wherein the piston rod 52 projects in a step-shaped space 54 of the housing 45 while the piston rod 53 projects in a step-shaped 55 of the housing 46. In the area of the smaller diameter of the step-shaped spaces 54, 55, each housing 45, 46 accommodates two conduits 56, 57; 58, 59. The conduits 56; 58 are in communication with a supply line for a concentrate while the conduits 57; 59 are in connection with the mixing container as can be seen from FIG. 4. All the conduits 56, 57; 58, 59 are provided with alternatingly acting check valves 60, 61; 62, 63. 
     In the area of the larger diameter of the step-shaped spaces 54, 55, pipes 64, 65 are arranged which serve for guiding pistons 66, 67 which are connected respectively to the piston rods 52, 53. The pistons 66, 67 have different diameters and are each provided with a spiral-shaped face 68, 69. The pistons 66; 67 can be rotated so that depending on the rotational position of each piston, connections 70; 71 which for example lead to the atmosphere can be closed by the piston 66, 67 upon axial movement of the plunger 51. Through such a provision, the maximum concentrate quantity to be supplied is limited. 
     For obtaining rotational movement, the pistons 66, 67 are provided with extensions 72, 73 through which bolts 74; 75 are mounted transverse to the piston axis. The bolts 74; 75 protrude through oblong holes 76, 77; 78, 79 located in the sleeves 43; 44 and project therefrom and are connected with their ends in not shown bore holes of the reverse members 41, 42. 
     As can be seen from FIG. 2, the cylinder space 50 is connected to the cylinder chambers 10, 11 via bore holes 80, 81; 82, 83 (see also FIG. 5) wherein the bore hole 80 is separated from the bore hole 82 by the plunger 51. 
     Furthermore, it is to be noted that the plunger 51 is sealed against the pistons 66; 67 by respective sealing means. 
     As can be seen from FIGS. 4 and 5, the mixing container 2 is arranged below the dosing device 1 and contains several superposing chambers 83, 84, 85 which are connected to each other by at least one narrow gap 86, 87, 88. The so formed upper chamber 83 is connected to the dosing device while the lower chamber 85 is connected via the outlet 3 to for example a pressing machine. 
     After having described the individual parts of the apparatus according to the invention, the mode of operation will now be illustrated in detail: 
     When the apparatus according to the invention has the position as illustrated in FIG. 2, pressure medium flows through the bore hole 31 via groove 38a, radial bore holes 36 and axial bore hole 37 to impinge piston 7 of the control slide 5. Consequently the control slide 5 is axially moved until the piston 9 abuts the locking ring 18. During this axial movement of the control slide, the duct 14 is closed by the piston 7 while the duct 12 is connected to the cylinder chamber 10. Consequently, the cylinder chamber 11 is separated from the duct 12 and is connected to the duct 13. As soon as this has happened, the pressurized main fluid flows through the duct 12 into the cylinder chamber 10 and finally through the conduits 80 and 81 and impinges the plunger 51 which is consequently moved to the right. Therefore, the main fluid located within the cylinder space 50 is discharged via the conduits 82 and 83 and the cylinder chamber 11 into the mixing container via the duct 13. During the movement of the plunger 51 towards the right, the piston 67 is smultaneously moved to the right and draws in concentrate into the cylinder space 55 via conduit 58. During the suction of concentrate through conduit 58, conduit 59 which is in connection with the mixing container 2 is blocked by the check valve 63. Simultaneously with the movement of the piston 67 towards the right, the piston 66 is moved in the same direction. During this movement, the piston 66 closes at first the connection 71. Thereafter, the piston 66 presses the concentrate located within the cylinder space 54 into the mixing container 2 via conduit 57 while the conduit 56 is blocked by means of check valve 60. Following the movement of the pistons 66, 67, the reverse members 41, 42 have also moved to the right as did also the retainer disk 39 because of the exerted force of spring 23. When spring 23 is almost completely released, the reverse ring 41 abuts the retainer disk 40 and further moves the retainer disk 40 to the right thereby tensioning spring 24. In the now obtained end position of the pistons 27, 28, the groove of the piston 27 is connected with the through hole 32 which is connected to the return pipe and the groove of piston 28 is connected to the through hole 34 which is communicating with the pressure medium source so that the course of movement of the apparatus is now reversed in analogous manner. 
     It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of apparatus for automatically producing solutions in predetermined dosages differing from the types described above. 
     While the invention has been illustrated and described as embodied in an apparatus for automatically producing solutions in predetermined dosages, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention. 
     Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that from the standpoint of prior art fairly constitute essential characteristics of the generic or specific aspects of this invention.