Patent Publication Number: US-3876108-A

Title: Dosaging device for liquid substances

Description:
United States Patent [191 Miiller, deceased et al.  
 [ DOSAGING DEVICE FOR LIQUID SUBSTANCES [76] Inventors: Horst Peter Rudolf Miiller, deceased,  
 late of Usmate Velate. Italy by Edeltraud Moller, born Lukas; Catya Mt&#39;iller; Martin Moller; Matheus Mt&#39;iller, all of Via Cavour No. 42. Usmate Velate, Italy heirs [22] Filed: Apr. 1, 1974 [2|] App]. No.1 457,096  
 [ Apr. 8, 1975 Primary E.\&#39;aminerStanley H. Tollberg [57] ABSTRACT A dosaging device for liquid substances. provided with a Lukas punched-tape programmer or external push buttons. An actuating block means connects to the Lukas punched-tape programmer or external push buttons. a plurality of valves for the introduction of the liquid substances. a receptacle for the dosaging of liquid substances of tapered shape. a guide tube inside said receptacle. A movable lever-detecting probe means sensitive to the liquid substances operatively connects to the actuating block means connecting to the Lukas programmer or the outer push buttons. and regulates the position of the probe with the guide tube inside the receptacle and controlling the opening and closing of the plurality of valves for the introduction of the liquid substances. such that upon the reaching of a predetermined level detected by the probe, the actuating block means controls the closing of the valves.  
 [0 Claims, 2 Drawing Figures DOSAGING DEVICE FOR LIQUID SUBSTANCES The present invention relates to a dosaging device for liquid substances, provided with a movable leveldetecting probe.  
  The present invention concerns a dosaging device for liquid substances which is provided with a movable lev el-detecting probe adapted to effect the dosaging of a plurality of liquid substances which are fully compatible with a washing phase particularly useful for industrial use.  
  It is known that in industry the dosaging of liquid substances has up to now been effected with the use of techniques which are absolutely non-functional from the standpoint of the efficiency and use of labor. As a matter of fact, for the dosaging of substances or compounds in liquid state there have been used entirely empirically receptacles of known volume in order manually to transfer the required quantities of the various liquid substances or pumps mounted between the containers of the substances to be dosed and the user.  
  The drawbacks of the dosaging methods and means concern in particular the excessive use oflabor and the substantial time required. In particular, the pumps, although representing a substantial advance over entirely manual dosaging, have a substantial limit of use in view of the multiplicity of frequently incompatible chemical substances which it is necessary to meter. Due to this incompatibility, it is necessary to take the pumps apart between successive dosagings and to effect a careful washing thereof, the pumps being therefore better suited to effect the transfer of specific chemical substances than in effecting a precise dosaging.  
  It is an object of the present invention to provide a device which is adapted to effect. with very great precision, the dosaging of predetermined volumes of a plurality of substances or compounds in liquid state with the use of a movable level detector which is sensitive to the liquids and the position of which is axially adjustable within a calibrated dosaging receptacle.  
  It is another object of the present invention to provide a dosaging device for liquid substances, the operation of which is entirely automated, so that the succession of the stages of dosaging liquids which may possibly be different is effected, for instance, on the basis of a program which is punched on a tape, without requiring further manual interventions at the same time and permitting a substantial reduction in the operating cost. Alternatively, the dosaging device in accordance with the present invention can be provided with a series of push buttons adapted to permit a digital asynchronous manual entry of the operating phases.  
  Still another object of the present invention is to provide a dosaging device of reduced dimensions, with a dosaging receptacle of tapered shape, and provided with a level transmitting probe sensitive to liquids and capable of axial registration within the receptacle.  
  It is yet another object of the present invention to provide a dosaging device for liquid substances in which the introduction into the dosaging receptacle of different liquids to be dosed is effected by valves of differentiated cross section in parallel as a function of the physical characteristics and volumes of the different liquids, the transmitting probe being suitably insulated and protected from spurious contacts by a guide tube in which it moves, the guide tube being internal to and coaxial with the dosaging receptacle the emptying of which takes place from below through the opening of the valve with diaphragm (or zero volume).  
  The liquid dosaging device in accordance with the present invention is characterized essentially by the fact that it comprises a dosaging receptacle for liquid substances of a tapered shape, a level-detecting probe sensitive to said liquid substances and connected by suitable means to an actuating block adapted to regulate the position of the probe within a guide tube within the said dosaging receptacle and of controlling the opening and the closing of a plurality of valves for the introduction of said liquid substances, for which purpose, upon the reaching of a predetermined level, detected by the probe, the said actuating block effects the closing of the said feed valves, means furthermore being provided which are adapted to permit the emptying of said receptacle, as well as means adapted to effect the washing of the guide tube and of the receptacle.  
  With the above and other objects in view, the present invnetion will become more clearly understood from the following detailed description of a preferred embodiment, given solely by way of illustration, and not of limitation, in the accompanying drawings in which:  
  FIG. 1 is a front view, partially in section, of the dosaging device in question; and  
  FIG. 2 is a block diagram explaining the operating connections of the dosaging device in accordance with the present invention.  
  Referring now to the drawings and more particularly to FIG. I in which the reference number I indicates generally the dosaging device in accordance with the present invention, there can be noted a dosaging receptacle 2, the guide tube 3 and the probe 4 connected by the wire 5 to the pulley 7.  
  The dosaging receptacle 2, in accordance with the embodiment shown in the drawing, results from the penetration of a lower cylindrical section into a frustopyramidal section 9.  
  The essential characteristic of the dosging receptacle 2 if that its cross section decreases from the top to the bottom so as to permit precise dosaging of volumes which vary from a few tens of a cc to a few ten thousands of a cc, while satisfying the fundamental requirement that the dosaging container takes up only a small amount of space. In accordance with what is shown in the drawing, the dosaging container 2 is supported by a plurality of legs 18. In particular, the cylindrical lower section 10 of reduced volume lends itself for the dosaging of small amounts of additives, coloring substances, etc., in liquid state. The valve 6, of the zero-volume type, is fastened in the outlet of the section 10 at the conduit 21 into which the dosaged liquid is introduced for its use.  
  The level probe, indicated generally as 4, is adapted to detect the attaining of a predetermined level only in its lower part I4, the balance thereof being insulated in order to avoid possible undesired contacts with the liqaid to be closed. As a matter of fact, such spurious contacts transmitted by the probe 4 through the wire 5 up to an actuating block (not shown) would be interpreted by the latter as the reaching of the liquid level to be dosed, resulting in the automatic closing of the feed valve 30 for said liquid within the dosaging device. The feed valves 30 are located in the upper part of the receptacle 2 in such a manner as to permit the filling thereof from above. The tube 3, within which the probe 4 moves, is perforated at its lower end in order to promote the passage of the liquid present in the container 2. The two disks 22 with which the probe 4 is provided are arranged so as to maintain the position of the latter perfectly vertical within the tube 3. Furthermore the disks 22 are perforated in order to avoid the possible floating of the probe on the liquid.  
  it is important to note that the tube 3, in addition to serving the function as guide for the probe, prevents any undulations of the surface of the liquid to be dosed from causing errors in the transmission of the level effected by the probe 4.  
  The axial positioning of the probe 4 within the receptacle 2 is preprogrammed manually by digital control or automatically by punched tape. In this latter case, the dosaging device in accordance with the invention will be provided with a Lukas model 3675 programmer or with any other model of Lukas perforated-tape programmer suitably modified.  
  Obviously. since the programming of the positioning of the probe 4 is effected on the basis of the correspon dence between the volume of liquid to be dosed and the level reached by the liquid within the container 2, it is clear that the dosaging container 2 is calibrated in such a manner that its volume-level ratio is known in ad vance for each cross section thereof. For this purpose it is of interest to note that the frustopyramidal shape with cylindrical lower section of the container 2 makes it possible to establish in extremely easy and precise fashion the correspondence between level and volume.  
  The actuating block (not shown) is connected electrically to the block 8 of FIG. 1 comprising conventional microswitches and kinematic mechanisms, in cluding a motor reducer on the shaft of which the pulley 7 is keyedv The said pulley 7 is at one of the ends of the wire 5, the other end of which is firmly fastened to the probe 4. The wire is fully insulated so as not to be affected by a possible splattering liquid to which it may be subjected during the filling of the dosaging container 2, and it has the twofold function of supporting the probe 4 and of connecting it electrically via the kinematic mechanisms and microswitches with the actuating block.  
  The positioning of the probe and the axial placing thereof are effected precisely by acting manually on the actuating block, of conventional type, or inserting a punched tape into a Lukas programmer. At this point, the actuating block, controlled by the programmer and on basis of the digital manual controls, in addition to positioning the probe 4 via the block 8 and the wire 5 controls the opening of the valves for the introduction of the liquid provided at the top in the dosaging receptacle (the liquid feed valves can, for instance, be provided on top, in position corresponding with each of the faces of the frustopyramidal section of the receptacle 2 The probe, having been brought to a level corresponding to a predetermined volume of liquid, will signail the introduction of said volume when it comes into contact with the liquid. The contact will cause, in accordance with conventional techniques, the forming of a pulse which effects the closing of the feed valves 30 by the said actuating block. The actuating block of conventional type used is preferably of electronic type and comprises essentially an imbalance bridge the output of which constitutes the input signal of a differential amplifier of high gain and high input impedance. One of the sides of the bridge is formed of a series of impedances which can be disconnected and connected either by manually operating the corresponding push buttons made available on a suitable outer support or by using a Lukas programmer based on corresponding punchings in a tape. The imbalance of the bridge causes the actuation of a rebalancing potentiometer on a side of the bridge adjacent the side of the impedances which can be connected and disconnected, said potentiometer being controlled by the conventional kinematic mechanisms included in the block 8 of FIG. 1 until the balancing of the bridge and the consequent stopping of the probe 4 at the predetermined pre-programmed level. During this phase, the actuator will keep the feed valves 30 open; the closing thereof being controlled by the actuator on basis of the pulse coming from the level probe at the moment when the latter has come into contact with the liquid substance. In accordance with a preferred embodiment of the present invention, the said liquid-sensitive level probe is a probe of electricai type with discharge to ground. It is important, however, to note that the dosaging device in question may use any level probe, provided that it is sensitive to liquids and can be recorded axially on basis of a predetermined numerical value corresponding to a given volume to be admitted, punched on a tape and inserted manually be depressing external push buttons. The characteristics of the actuating block furthermore do not constitute a specific object ofthe invention, it being intended that the functions effected by the block de scribed may be obtained by other known devices using a technique even other than electronics, for instance, hydraulic or pneumatic devices.  
  The operation of the dosaging device in accordance with the present invention may be exemplified by reference to the block diagram of FIG. 2 in which parts identical to those of FIG. 1 are indicated with the same reference number, to which a prime mark has been appended.  
  Referring to FIG. 2 in which the block 51 is intended to designate a Lukas punched-tape programmer or a series of push buttons, the input signal coming from block 51 controls the actuating block 52 which positions the level probe 4&#39; by means of the transducing kinematic mechanisms 8&#39;. At the same time, the actuating circuit controls the opening of the feed valves 30&#39; for the feeding of the liquid substances into the dosaging receptacle 2&#39;. Through the probe 4&#39; the condition of the receptacle (namely the level of liquid) is fed back to the actuating circuit 52, which, upon the reaching of the pie-determined pre-programmed volume on the block 51, controls the zeroing of the probe 4&#39; (by zeroing of the probe 4&#39; it is meant that the probe is brought to the lowest level permitted in the dosaging receptacle. Thereupon, either on basis of a punched tape or else by depressing a push button, there will be effected the opening of the discharge valve 6&#39; to permit the use of the liquids dosed and the actuating circuit will automatically bring about the feeding of liquid for the washing both of the guide tube 3 and of the dosaging receptacle 2. It is important to emphasize the necessity of this lastmentioned phase which, in addition to effecting the proper washing of the dosaging device permits the complete utilization of the liquids discharged by the valve 6, which liquids, in view of the small volumes dosable for instance 50 cc, would be dispersed differently on the inner surface of the conduit 21 without arriving at the use. Finally, it should be noted that the introduction of the liquid substances to be dosaged may be effected, for each liquid preferably, through two valves in parallel and specifically one solenoid vlave for dosaging small quantities and one valve for medium and large quantities. The washing after the discharge of the dosed liquids is effected automatically and in programmed time. However additional washings may be effected automatically through specific punchings on the tape or by manual control. It will be noted that the feeding of the liquids into the dosaging device, effected through two valves in parallel having different capacities, permits tolerances in calibration which are maintained within the limits of i2 percent and 12.5 percent respectively for the maximum and minimum valves.  
  Although the present invention has been described with reference to the accompanying drawings and a particularly preferred embodiment, it is clear that variants and/or changes may be made within the present invention, and the illustrated embodiment is given by example only and not in a limiting sense.  
 I claim:  
  1. A dosaging device for liquid substances, provided with a Lukas punchedtape programmer or external push buttons, comprising an actuating block means connecting to said Lukas punched-tape programmer or external push buttons,  
 a plurality of valves for the introduction of said liquid substances,  
 a receptacle, for the dosaging of liquid substances, of  
 tapered shape,  
 a guide tube inside said receptacle,  
 a movable level-detecting probe means sensitive to said liquid substances and operatively connected to said actuating block means connecting to said Lukas programmer or said outer push buttons, and for regulating the position of said probe with said guide tube inside said receptacle and controlling the opening and closing of said plurality of valves for the introduction of said liquid substances, such that upon the reaching of a predetermined level detected by said probe,,said actuating block means controls the closing of said valves,  
 means for permitting the discharging of said receptacle, and means for effecting washing of said guide tube and of said receptacle.  
 2. The dosaging device for liquid substances, as set forth in claim 1, wherein said means connecting said level probe means to said actuating block means are formed of an insulated wire and of a block, constituting a conventional kinematic mechanism,  
 a pulley keyed onto a shaft of a motor reducer,  
 said wire is fastened at one of its ends to said probe means and at its other end to said pulley keyed onto the shaft of said motor reducer with which said block of conventional kinematic mechanism is provided connected electrically to said actuating block means.  
 3. The dosaging device for liquid substances, as set forth in claim 2, wherein said actuating block means comprises an imbalance bridge having an output,  
 a differential amplifier operatively connected at said output, said probe means constitutes an electrically operating probe of the discharge-to-ground type and is completely insulated, with the exception of an end thereof which faces downward, such that an axial registration of said probe within said guide tube, the actuation of a balancing potentiometer constituting a part of said bridge, and the opening of said valves for the introduction of said liquid substances correspond to an imbalance of the bridge. 4. The dosaging device, as set forth in claim 3, wherein said level probe means of electric discharge-toground type for producing a discharge pulse at the moment when it comes into contact with a liquid substance, said pulse being transmitted through said wire to said actuating block means. 5. The dosaging device, as set forth in claim 1, wherein said guide tube of said probe means is fastened within and coaxially to said dosaging receptacle and is perforated at a bottom, said probe is provided with two perforated plates of a diameter slightly less than the diameter of said tube. 6. The dosaging device, as set forth in claim 1, wherein said plurality of valves comprises a plurality of valves equal to the number of different liquids to be dosed. 7. The dosaging device, as set forth in claim 1, wherein said plurality of valves comprise two admission valves in parallel for each liquid to be dosed, one of said valves being adapted for the introduction of medium to large volumes of liquid, and the other said valves being adapted for the introduction of small volumes. 8. The dosaging device, as set forth in claim 1, wherein said dosaging receptacle of tapered shape is developed from axial penetration of a frustopyramidal section into a cylindrical section, said means for permitting the discharge of the measured liquid substances comprises a diaphragm provided in the outlet of said cylindrical section. 9. The dosaging device, as set forth in claim 1, wherein said dosaging receptacle of tapered shape is developed from axial penetration of a frustopyramidal section into a cylindrical section, said means for permitting the discharge of the measured liquid substances comprises a zero-volume valve provided in the outlet of said cylindrical section. 10. The dosaging device for liquid substances, as set forth in claim 1, wherein said means for permitting the washing of said guide tube and of said receptacle is formed of at least one feed valve an opening of which is automatically controlled by said actuating block means after the opening of a diaphragm valve programmed by punching on tape or controlled by depressing an outer push button.  
  l i i