US3893470A

US3893470A - Liquid mixing and distributing apparatus

Info

Publication number: US3893470A
Application number: US471208A
Authority: US
Inventors: John Macphee; Harold W Gegenheimer
Original assignee: Baldwin Gegenheimer Corp
Current assignee: Baldwin Gegenheimer Corp
Priority date: 1974-05-20
Filing date: 1974-05-20
Publication date: 1975-07-08
Anticipated expiration: 1992-07-08
Also published as: JPS5912335B2; DE2521944A1; DE2521944C2; JPS50160869A

Abstract

In liquid mixing and distributing apparatus a unitarily formed tank provides a first compartment for receiving a primary liquid and a second compartment for receiving a secondary liquid. Float means in the first compartment serves to control the introduction and release of primary liquid into the first compartment. The same means also interconnects with a piston which is positioned to be immersible in the secondary liquid. By this interconnection, rise of liquid in the first compartment lowers the piston into the second compartment causing a metered portion of its liquid content to overflow into the first compartment, where admixture of the two liquids occurs. Adjustable blocking means are provided for limiting the degree of immersion of the piston and thus varying the quantity of secondary liquid which is displaced into the first compartment.

Description

United States Patent MacPhee et a1.

July 8, 1975 LIQUID MIXING AND DISTRIBUTING APPARATUS Inventors: John MacPhee, Rowayton; Harold W. Gegenheimer, Darien, both of Conn.

[73] Assignee: BaldwimGegenheimer Corporation,

Stamford, Conn.

[22] Filed: May 20, 1974 [2]] Appl. No.: 471,208

[52] U.S. C1 137/10l.27; 137/l01.3l [51] Int. Cl. G05d 11/13 [58] Field of Search..... l37/10l.21, 101.25, 101.27, 137/1013] [56] References Cited UNITED STATES PATENTS 395,651 1/1889 Blessing 137/1013] 3,358,704 12/1967 Wyatt et a1. .1 137/1012] Primary Examiner-Robert G. Nilson Attorney, Agent, or FirmSt. Onge Mayers Steward & Reens [57] ABSTRACT In liquid mixing and distributing apparatus a unitarily formed tank provides a first compartment for receiving a primary liquid and a second compartment for receiving a secondary liquid. Float means in the first compartment serves to control the introduction and release of primary liquid into the first compartment. The same means also interconnects with a piston which is positioned to be immersible in the secondary liquid. By this interconnection, rise of liquid in the first compartment lowers the piston into the second compartment causing a metered portion of its liquid content to overflow into the first compartment, where admixture of the two liquids occurs. Adjustable blocking means are provided for limiting the degree of immersion of the piston and thus varying the quantity of secondary liquid which is displaced into the first compartment.

10 Claims, 12 Drawing Figures PATENTEU JUL 8 975 SHEET WM w y dk 1 LIQUID MIXING AND DISTRIBUTING APPARATUS The present invention relates to a liquid mixing and distributing apparatus and more particularly to apparatus for producing a solution having a desired combination of ingredients and thereafter controllably supplying the solution to an end use destination. One primary use for the invention is in the printing industry.

BACKGROUND AND BRIEF DESCRIPTION OF INVENTION Offset printing presses are generally provided with a reservoir (generally the "water fountain pan) which is filled with a water solution of gum arabic and a slight proportion of chromic or phosphoric acid. The dampening rollers of the press apply this etch and gum" water solution to the non-printing portions of the printing plate on the plate cylinder of the press, thus insuring that no ink from the inking rollers will be received on the dampened portions of the plate. The proportions of a particular etch and gum solution are dictated by a number of factors, including the type of ink used, the nature of the printed work, the color being printed, and the type of paper to be printed.

It has proven impractical to prepare and store large quantities of etch and gum solution over extended periods of time because of various kinds of deterioration that can occur in the course of such storage. On the other hand, some conditions of press operation may require that relatively great quantities of solution be supplied in a continuous run. To accommodate both these considerations, apparatus has heretofore been provided which can, under automated control, provide a continuous succession of freshly mixed batches of solution, with the added possibility of varying the proportions of the mix from time to time as may be required by different printing assignments. An early version of such apparatus is disclosed, for example, in US. Pat. No. 3,166,095, issued Jan. 19, 1965, in the names of Harold W. Gegenheimer, Andrew N. Stad, and Philip E. Tobias, and hereby incorporated by reference.

A critical element of batch mixing apparatus of the kind referred to is the means provided for measuring precisely and reliably the amount of etch and gum concentrate to be added to a known guantity of water and for conveniently changing that amount under the control of the operator. in US. Pat. No. 3,166,095, referred to above, this function is accomplished by means of a metering tank which is intermittently filled to capacity with etch and gum concentrate, but from which only a predeterminable fraction of the stored quantity is withdrawn for admixture with the water solution. In a later development of Baldwin-Gegenheimer Corporation, the assignee of the present invention, a similar function is provided by a repetitively refilled opentopped tank which is floatably supported in the water solution to which the metered concentrate is to be added. Above the open top of the tank there is positioned a fixed piston" which can enter the tank if the tank is moved in the upward direction. In operation of the apparatus, such upward movement of the tank actually occurs as increasing amounts of water are fed into a water-receiving space which surrounds the metering tank. The resulting entry of the piston into the tank displaces some part of the concentrate and causes it to overflow into the circumambient water solution.

By preadjustment of the vertical position of the piston the amount of concentrate released for mixture with the water as the water approaches its maximum permitted level can be predetermined with entirely acceptable accuracy. When the water has in fact reached its maximum level, a batch solution of the desired constituancy will have been produced and will be available for feeding (i.e. under operator or automatic control) to the press fountain pan (or alternatively to a central reservoir from which destribution to a number of presses is to be accomplished).

The success of batch mixing of the kind just described has been such as to lead to continuing expansion of its field of application and to a demand for solution mixing and distributing apparatus of lower cost and still greater accuracy. The present invention is concerned with meeting these requirements. The invention provides in a highly compact assembly (i) a metering storage compartment for the etch and gum (or corresponding) concentrate and (ii) a compartment in which the concentrate is mixed into the water solution. The first of these compartments has an overflow point above which flow of concentrate may occur from the concentrate-containing space into the water-containing space. A liquid-supply system is provided in connection with the concentrate storage space, which in the normal operation of the apparatus, will tend to maintain a fixed minimum level of concentrate in the storage space. Extending downwardly into the concentrate storage space is a movable piston, which, as it is moved in the downward direction so as to become progressively immersed in the concentrate, raises the level of the concentrate to the overflow point, thus causing it to pass into the water-containing mixing chamber. The quantity of concentrate which overflows depends upon the extent of permitted downward motion of the piston. As will be further explained in the detailed description of the invention, this factor is made adjustable by the operator, so that different proportions of water and concentrate can be obtained as required by varying conditions of operation of the printing presses with which the mixing apparatus is to be connected.

The water with which the etch and gum concentrate is to be admixed is supplied to the mixing compartment under the control of a float positioned in this compartment. This float may also be connected with control mechanisms which enable it to initiate in-flow of water into the compartment whenever the water level reaches a predetermined minimum and to terminate in-flow when a predetermined maximum level is attained. Operative means interconnect the float with the displacement piston previously described in connection with the concentrate storage chamber, and by this means the piston is caused to increase its immersion in the concentrate as the water level rises and to be progressively withdrawn from the concentrate as the water level falls toward its permitted minimum. in this way, rising of the water level initiates the metered introduction of etch and gum concentrate into the mixing compartment. Moreover, as will further appear in subsequent description, the collocation of principal operating parts as so far described produces a highly compact and low cost assembly of the entire apparatus.

Other aspects and advantages of the invention will become apparent upon consideration of the following description taken in connection with the accompanying drawings. in the drawings:

FIG. 1 is a perspective view of the external aspects of one embodiment of the invention;

FIG. 2 is an enlarged plan view of the apparatus of FIG. 1 with part of the top structure cut away;

FIG. 3 is an irregular sectional view taken on line 33 of FIG. 2, but with all elements of that Figure restored,

FIG. 4 is a partial section taken upon line 44 of FIG. 2;

FIG. 4A is an enlarged and segmented plan view of certain elements of FIG. 4',

FIG. 5 is a section (with upper part deleted) taken upon line 5-5 of FIG. 3;

FIG. 6 is a section taken upon line 6-6 of FIG. 3',

FIG. 7 is a schematic assembly of certain of the principal functional parts shown in FIGS. I through 5;

FIG. 8 is an enlarged detail, in section and partially broken away, of part of the structure shown in the left hand portion of FIG. 4;

FIG. 9 is a section taken on line 9--9 of FIG. 8;

FIG. 9A is a section taken on line 9A-9A of FIG. 8; and

FIG. 10 is an irregular section taken upon line I010 of FIG. 8.

DETAILED DESCRIPTION OF THE INVENTION Referring to FIG. I there is shown in that Figure the external configuration of the principal parts of the invention assembled in their normal working relationship. This assembly has as its base portion a casing or tank II) which is so formed as to be readily selfsupported upon any level surface. In an embodiment of the invention which is preferred because it leads to low cost both in terms of material and fabricating requirements, the tank 10 consists of a unitary (one-piece) molded enclosure of liquid and etch-resistant plastic material, for example, polyvinyl chloride. It is provided at its upper edge with a surrounding outwardly directed lip I5 which, as appears in FIG. 4, may be slightly offset from the plane of the vertical tank wall to provide an inwardly directed ledge 17 for the support of a cover plate 20.

Supported on cover plate 20 is an inverted container which, as will be further explained at a later point, is adapted to provide storage for from one to several gallons of a concentrated etch and gum solution or other concentrated solution intended in the operation of the apparatus to be admixed with water or other appropriate diluent or solvent. For present purposes it is sufficient to note that the container 30 as illustrated comprises a water-tight and air-tight assembly consisting of a cylindrical sidewall 32 of plastic, an imperforate end wall 34, a generally similar wall 36 at its opposite extremity and take-up means or tie rods 38 for maintaining the end walls in firm assembly with the cylindrical sidewall 32. In the inverted position in which it is shown the container 30 has a downwardly directed outlet system 40 which will be described in detail at a later point.

Also supported on the cover plate 20 are two remov able (but normally secured)

casings

44 and 46 which enclose electrical and mechanical control devices to be further described at a later point. A water supply pipe 48 is also operatively connected to and through the cover plate 20, as will further appear. Also shown in FIG. I is a control assembly 50 which will be shown to have an important role in controlling he proportions of the liquid mix which it is the function of the assembly 10 to produce. At the right hand extremity of the assembly there is shown a liquid outlet conduit 60, also to be further referred to at a later point.

Referring now to FIG. 3, in which many of the items so far described will be readily identified, it will be seen that the tank 10 as viewed in longitudinal section comprises a first relatively large liquid-receiving compartment which occupies the greater portion of the right hand part of the tank structure and has wing portions 70a extending to the left end of the structure. It is the function of this compartment to receive a substantial quantity of primary liquid (e.g. water) which in the course of operation of the apparatus is to be admixed with a secondary constituent such as an etch and gum concentrate. To the left of this first compartment. but in proximity to it, there is provided a second, smaller compartment 75, the wall structure of which is shown as being formed continuously with the wall structure of the compartment 70. It is the function of this compartment to receive from the reservoir 30 the secondary liquid or concentrate. This second liquid is introduced into the compartment from the reservoir 30 by means of the outlet system 40, already referred to. The details of this outlet system are significant to the functioning of the present invention and will therefore be described in detail at a later point. It is sufficient at this point, however, to say that the conduit system has a primary outlet 252 through which down-flowing liquid from the reservoir 30 is introduced into the chamber 75. The combination of the inverted reservoir 30 and the outlet system 40 provides a liquid level maintaining system of the type sometimes referred to as a chicken feeder". In such a system the balance between the partial vacuum existing in the upper portion of the reservoir 30 and the weight of the liquid column seeking egress through the outlet 252 causes a substantially constant level of liquid to be maintained in the chamber 75 as indicated at 78.

As may be seen by joint consideration of FIGS. 2 and 3, the compartment 75 is an open top basin having a bottom wall 75a formed with considerable spacing between it and the supporting foundation of the total tank assembly 10. On three sides of this basin its lateral bounding wall is connected to and merges into the bounding wall of the tank 70 by means of a horizontal bridging part 75b. As appears more clearly in FIG. 5, narrow extensions 70a of the compartment 70 extend along and in effect enclose the lateral walls of the compartment 75. It will be apparent that by virtue of this arrangement the compartment 75 may be said to have an overflow point above which liquid 78 contained in that compartment will overflow the bounding surface 75b and drop into the larger mixing compartment 70. The significance of this arrangement and the means by which overflow from the compartment 75 into the compartment 70 can be made to occur will be explained in due course.

Reference will now be had to the liquid supply means by which the liquid in the tank 70 may be maintained between a predetermined minimum level and a predetermined maximum level. These means include as a principal functioning element a float 80 which is constituted of a body of material having a significantly lower specific gravity than water. This body may comprise, for example, a rigid block of closed cell polyvinyl chloride foam. On the upper surface of the block 80 there is provided a stainless steel plate 82 which, among other things, serves as a weight-increasing element to enable the block to perform a counterbalancing function which will be described at a later point.

As is best shown in FIG. 6, there is attached to the plate 82 an upwardly extending U-shaped bracket 85 secured by bolts 83 which project into the float 80. This bracket has vertical legs 85a and a transverse part 85b joining these legs. At the central region of the transverse part there is a slot 850 extending at right angles to the axis of the transverse part. (See FIG. 40)

Still referring primarily to FIG. 6 (taken with FIG. 4), there is supported well above the central region of the float block 80 and within the covermounted casing 44 a twoway toggle switch 88 having a power-connected contact 88a and two alternatively usable contacts 88b and 88c which, as will later appear, are respectively connected through separate solenoid valve controls to ground. This switch is of the over-center toggle variety, with its active switching member 88d connected through a spring linkage 88 to a movable actuating head 88f. An operative connection between the switch 88 and the float block 80 is provided by means of a push rod 90 which at its upper end is attached to the switch actuator 88f by a linkage assembly 91 coacting with a fixed mounting bracket 92. The rod 90 extends downwardly through the slot 850 in the transverse bracket part 85b (FIG. 4) so that its lower end approaches but does not contact the plate 82.

Circular collars

93a and 93b are attached to the intermediate region of the rod in such a way (e.g. by set-screws) that their relative positions can be adjusted or preset by the operator of apparatus. With this arrangement of parts it will be seen that as the float 80 moves upward (i.e. during a period in which water is being fed from a supply source into the tank 70) a point will be reached, as represented in FIG. 4, at which the transverse bracket part 85b will engage the collar 93b and cause the push rod to move the switch actuator 88f (FIG. 4) into its uppermost position. Thiis action will snap the powerconnected switch element 88a into contact with switch terminal 88c. As will be more fully explained in the description of FIG. 7, this will simultaneously cut off the incoming supply of water to the tank compartment 70 and will initiate an outflow of water from the bottom of the tank, thus lowering the water level in the tank.

Because, as previously indicated, the switch 88 is of an over-center variety, the reduction in water level will not immediately effect the condition switch. However, when the float 80 has dropped significantly (i.e. with decreasing water level) a point will be reached at which the transverse bracket part 85b will contact the upper surface of the rod collar 93a, thus drawing the rod in the downward direction. When this happens, the switch 88 will be thrown into its alternate position with the contacts 88a and 88b in engagement. Under these circumstances, as will subsequently be explained in detail, the outflow of water from the compartment 70 will be halted and the influx of a fresh supply of water will begin. This cycle will continue indefinitely unless interrupted by the operator of the equipment. It will be understood that the maximum and minimum levels which the water is permitted to attain can be predetermined in advance by up and down adjustment of the

rodborne collars

93a and 93b. In general, the maximum level selected will always be at some point significantly below the overflow point (75b in FIG. 4) of the secondary compartment and the minimum point will be at least high enough to prevent the float from grounding" on the floor of the compartment.

Before recapitulating the operation of the apparatus as so far described, reference may usefully be had to the right hand portion of FIG. 3 which shows in some detail the means by which water is withdrawn from the compartment 70. This means comprises a lever arm I00 fulcrumed to the end wall of the apparatus casing as indicated at 102. The lower end of the lever arm, which is spring biased to the right, carries a frustoconical, partially hollow cap or cover member I05. In the position shown in FIG. 3, this cap engages a bulkhead fitting or gasket 107 having a central opening which leads to an outlet conduit 60. When the lever arm is rotated clockwise about the fulcrum 102, the cap necessarily moves away from the fitting 107, thus permitting water to be drawn from the tank compartment 70 into the conduit 60. To prevent the cap from becoming vacuum locked to the fitting I07, the latter is provided at its upper edge with an opening by which the passage to the conduit 60 is vented into a vertical duct 112 extending above the maximum attainable level of the liquid within the compartment 70. Flow of liquid into and through the conduit 60 to an end-use station (e.g., a press fountain) may be effected either by gravity flow or by use of a pump attached to the conduit.

The overall operation of the water level control system as so far described may best be summarized by reference to FIG. 7, in which items identified in the Figures previously discussed bear similar numerals. In the condition of the apparatus shown in FIG. 7, the water level in the compartment 70 has reached its prescribed minimum and the float 80 is in the lowest position which it can attain with the indicated position of the stop collar 930. In these circumstances, it may be assumed that the switching element 88a has snapped over from the dotted line position in which it engages contact 88b to the full line position in which it is shown in FIG. 7. The result of this transition is that solenoid which in its energized position holds the lever 100 in the illustrated dotted line position will have been de-energized, with the consequence that the closure cap 105 has moved into engagement with the fulkhead fitting 107 (i.e., as shown in full line illustration), thus terminating flow of water to the outlet conduit 60. Concurrently, the solenoid valve 125, which is normally closed, is energized and moved to its open position, thus allowing water to enter the compartment 70 through the supply conduit 48, one part of which (labelled 48a) extends into the lower region of the compartment. The resulting interflow again raises the water level in compartment 70 and moves the float 80 in the upward direction, a process which continues until the switch element 88a snaps into engagement with contact 88b. At this point, solenoid valve is again deenergized and solenoid 120 is energized, thus starting a new cycle of drain-and-refill. This process will continue until the apparatus as a whole is de-energized by opening the main power switch 130. In comparing the several Figures of the drawings it will be found that other Figures (particularly FIGS. 1 and 3) indicate the mechanical location of items such as the solenoid 120, its solenoid valve 125, and the switch which have been mentioned for the first time in the description of FIG. 7.

Having now described completely the system of water level control provided in connection with the primary tank compartment 70, it is in order next to describe the means by which this system also functions to control the supply of measured quantities of etch and gum solution from the secondary tank compartment 75. Referring particularly to FIGS. 3 and 6, it will be seen that each of the vertical float-attached bracket parts 85a is provided with a pair of spaced pivot pins 140 and 141. Each of the upper ones of these pins has rotatably secured to it a lever arm 145 which is further rotatably secured to and supported by a fixed fulcrum provided by a pin or bolt 147. Each of the bolts 147 is in turn held in place by a vertical bracket 148 having a secure attachment to the cover plate 20 of the assembly as indicated at 150. Each lever arm extends some distance to the left of the fulcrum pin 147, being provided near its left extremity with an upwardly directed notch 155. As may best be seen by joint consideration of FIGS. 2 and 3, each of the notches engages (from below) a horizontally extending support bar 160, the function of which will be detailed at a later point.

Referring once again to the combination of FIGS. 3 and 6, it will be seen that each of the brackets 850 has further attached to it a second lever arm 165 pivotally mounted on one of the bolts 141. This lever arm extends between the bracket 85a and the bracket 148, being pivotally attached to the latter by a pin or bolt 170. As may be discerned from the sectional view of FIG. 4, the two identical lever arms 165 are connected at their right hand extremities by a bridging piece l65b with which they jointly form a U-shaped assembly having its open end directed to the left in FIG. 3. The combination of the fixed vertical brackets 148, the levering

members

145 and 165, and the float-attached brackets 85a provides at each of two opposed extremities of the float 80 a pantograph arrangement the effect of which is to assure that the bracket parts 85a remain perpendicular to the floor of the tank compartment 70 as the float moves up and down. This in turn maintains the major surfaces of the float parallel with the floor of the tank and prevents the float from assuming an angular position which might cause it to frictionally engage any of the tank wall surfaces. As a further result of this arrangement, the horizontal or bridging part 8512 of the floatattached bracket system necessarily exerts completely vertical thrust upon the collars 91a and 91b attached to the switch actuating push rod 90. It is, of course, true that the pantograph mounting just described will cause the float 80 to move somewhat to the right as it rises from the low-level position which it occupies in FIG. 3 and to move back to the left as it sinks again in subsequent phase of the equipment operation. However, by virtue of the elongated slot 85c provided in the bracket part 85b (see FIG. 4A) this motion will not result in serious deflection or binding of the push rod 90.

It is now in order to consider the means by which motion of the float 80 is enabled to produce measured transfer of etch and gum concentrate (or other activating liquid) from the secondary tank compartment 75 to the primary compartment 70. Referring to FIG. 4, there will be seen suspended over the right hand region of the compartment 75 a displacement block or piston 200, indicated as being of generally square transverse section. The other relative dimensions of the block are shown in FIG. 2. The block extends over only a portion of the area of the compartment 75, leaving adequate clearance for the liquid conduit assembly 40. It is constituted of an appropriate liquid resistant material and in a preferred embodiment comprises high density polyvinyl chloride having specific gravity of about 1.4. Because of the latter characteristic it will tend to sink in the liquid 78 contained in the compartment unless it is supported by means other than its buoyancy in the liquid. The supporting means actually employed comprises in the first instance the horizontal bar I60 (FIG. 2). to which the piston is attached by spaced eye-bolts 205. The openings in these bolts are dimensioned to permit the piston to swing freely on the bar 160.

The bar itself has two separate means of support. The first of these comprises the pair of notched lever arms to which reference has already been made. The second comprises another pair of lever arms 2l0 which, as can be seen in FIG. 2, are joined in a U- shaped assembly by a cross-member 2l0b extending between them at their right hand extremities. The assembly is provided with oppositely disposed fulcrum points by extensions of the bolts or pins 147 supported in downwardly extending bracket arms 148. by virtue of this arrangement, downward movement of the crossmember 2101) will lift the piston-supporting extremities of the lever arms 210. These extremities, in turn, are provided with upwardly directed notches 2100 which are formed to receive the extremities of the support bar 160.

It is the function of the lever arm 210, coacting with additional means now to be described, to limit the possible downward motion of the displacement block or piston 200 without regard to the maximum upward motion of the float 80, and thus to permit controlled variation of the quantity of secondary liquid which the piston can cause to overflow the compartment 75. This is to be accomplished without concurrently altering the total quantity of primary liquid supplied to compartment 70. These objectives are achieved by providing operator-controlled means for adjusting the degree to which the left hand ends of the lever arms 210 (as seen in FIG. 4) can be drawn down by the weight of the displacement block 200. The particular means provided for this purpose comprises a circular blocking member 220 affixed to the lower end of a vertical adjusting rod 225. As best seen in FIG. 4, this blocking member engages the upper surface of the lever-connected crossbar 21Gb when the cross-bar reaches a certain level, that level being variable in accordance with the degree of downward extension of the adjusting rod 225. Upon such engagement of parts, downward motion of the displacement block 220 necessarily ceases regardless of its degree of submersion in the etch and gum solution 78. Assuming that a predetermined quantity of solution has been deposited in the compartment 75 before downward motion of the displacement block begins, it will be apparent that limitation of downward motion of the block automatically determines the fraction of this quantity which will be caused to overflow the boundary surface 75b, and thus effectively meters the amount of concentrate which can flow into intermixing relationship with the liquid in compartment 70.

As further appears in FIG. 4, the adjustment rod 225 is supported from the tank cover plate 20 by a fitting 227, which is internally threaded to engage external threads provided on the adjustment rod. Near its upper end the rod is provided with a knurled knob 228 by which it can be screwed up and down in the fitting 227. A pointed 229, also attached to the upper end of the rod, (although not rotatable with it) coacts with a scale 23], marked with appropriate fluid measurements (e.g. ounces per gallon), so that, after initial calibration of the system, the location of the pointer will indicate how much liquid is to be expelled from compartment 75 during a single cycle of operation of the apparatus. The amount can be increased at any time by turning the knob 288 to raise the blocking plate 220 to a degree indicated by the change of position of the pointer 229. Conversely, the amount can be reduced by effecting downward motion of the blocking plate.

While the lever arms 210 and the blocking plate 220 conjointly fix the limits of motion of the piston 200, it will now be shown that the occurrence of such movement in the first instance depends primarily upon action of the earlier described lever arms 145. In this connection, it may be assumed, for example, that the apparatus at the end of a filling and mixing cycle is in the condition in which it is shown in FIG. 4. It will be seen in this FIG. that the float 80 is at a high level, corresponding to attainment of the maximum desired level of the primary fluid. Under these conditions, the lever arms 145 have disengaged the piston support bar 160 as they are free to do because of the open nothces 155 by which engagement of the arms and the bar are accomplished. The piston thus stands supported solely by the independent lever arms 210. Consider, however, that the next phase of operation of the apparatus involves draining all liquid from the compartment 70. As such drainage occurs the float 80 will fall and the left hand extremities of the lever arms 145 will rise. At a certain point, the notches 155 will re-engage the crossbar 160 and, if effect, take over from the lever arms 210. In the preferred mode of operation of this system, the piston will be lifted by the lever arms 145 (ie as actuated by the falling float 80) until it nearly (but not quite) leaves the surface of the liquid in the compartment 75. Complete withdrawal of the piston from the liquid is undesirable because, if this were permitted, in any operation following such withdrawal the piston would be required to move an indefinite distance before beginning to raise the level of liquid in the cham ber 75. This would reduce the maximum realizable displacement of liquid.

It will be understood from the description of the apparatus as given so far that, with the exception of the fittings for the outlet conduit 60 (FIG. 3) and the parts 100 through I05 which coact with the outlet, all operating components of the apparatus are mounted on the tank cover plate 20. As previously indicated, the cover plate is supported by the peripheral ledge 17 formed inside the upper edge of the tank. However, it is further supported by a pair of U-shaped brackets 23 (FIGS. 3 and 4) so arranged that the closed part of the U bears in each case upon the floor of the tank compartment 70. By virtue of these arrangements the combination of the two

tank compartments

70 and 75 can be formed as a unitary structure of molded liquid resistant plastic material, for example, polyvinyl chloride which has been vacuum formed from sheet stock. Also, the flat cover plate may be formed of the same material. Accordingly, the cost of these major parts of the apparatus assembly is advantageously low. Moreover, the attachment of the various operating parts of the equipment to the cover plate 20 is readily accomplished with minimum expenditure of manufacturing time that the equipment as a whole is far less expensive than devices heretofore available for producing etch and gum solutions.

It will be understood that the reservoir 30 of secondary liquid (e.g. etch and gum concentrate) can be lifted as a whole from the cover plate 20 and refilled with fresh material at appointed intervals. This is desirable not only to permit refilling the reservoir when empty, but also in order to avoid the deterioration of quality which tends to occur in these materials if they are left unused for excessive periods of time. The outlet system 40 employed in connection with the reservoir 30 is the separate invention of John G. St. John, being claimed by him in US. application Ser. No. 476,894, filed June 6, 1974. It has special advantages in the present context which make description of its details appropriate. For purposes of such description reference may be had to FIGS. 8 through 10.

The outlet assembly 40 is removable as a whole from the end wall 36 of the reservoir 30 by means of a screw thread 241 formed at the upper end of the hollow cylinder 242 which forms the enclosure of the assembly. This thread engages a corresponding thread formed internally on a mouth-forming sleeve 30b which is attached to the reservoir end wall 36 and which extends downwardly through an appropriately sized opening formed in the tank cover 20. A gasket 2410 forms a tight seal between the end of the sleeve 30b and an annular flange 242a secured to the outer surface of the cylinder 242. The threaded end of the cylinder 242 encloses in tight-fitting engagement a second cylinder or sleeve 243 which has an inwardly tapered or countersunk end surface 243a. This is adapted to receive an interfitting closure member or stopper 244 which in turn is attached to an axially extending push rod 246. This rod is of such length that when the reservoir 30 is put in place on the tank cover 20 as shown in FIG. 8 the lower end of the rod will engage the floor of the tank compartment as indicated at 246a. In consequence, the stopper 244 is pressed away from the tapered opening 243a and liquid is free to flow into and through the cylinder 242. On the other hand, when the reservoir is moved away from the tank assembly (for refilling or otherwise), a compression spring 249 appropriately located at the lower end of rod immediately pulls the stopper into closed position, thus permitting the reservoir to be lifted and turned into an upright position without loss of liquid. This feature is not new in itself and is not described as novel. However, at the lower end of the cylinder 242, there are provided novel means for controlling the release of liquid into the tank compartment 70. These means comprise a cylindrical block 250 interfitted within the bore of the hollow cylinder 242. This block has a central opening for the rod 246 and two additional

circular openings

250a and 250b. The first of these receives a tubulation 252 which, in the illustrated orientation of the apparatus extends downwardly below the intended level of the liquid 78 in the compartment and provides the principal outlet for liquid from the reservoir 30 into the compartment 70. The opening 25Gb receives at its upper end a second tubulation 254 which is crimped and closed at its upper extremity as indicated at 2540 and which has in the sidewall of the crimped region a relatively small circular orifice 255. Through the opening thus provided, the liquid within the cylinder 242 is in communication with the main body of fluid in tank compartment 75 not only through the lower end of the opening but also through a small lateral orifice 256 which is located with its center line at the intended equilibrium level of the liquid pool 78. The effect of this arrangement is, first of all, that as long as a supply of liquid concentrate remains in the reservoir 30, the level of such liquid maintained in the receiving compartment 75 tends to stabilize at approximately the midpoint of the opening 256. That is to say, as long as the liquid pool is at or above the stated level, the air inlet path provided to the container through the still exposed part of the opening 256 is too restricted (by water surface tension or otherwise) to permit air bubbles to enter the enclosure 242. Accordingly, no air reaches the upper region of the container 30, and the partial vacuum maintained in that region prevents liquid from being released into the compartment 75, either through the tubulation 252 or through the opening 256.

It will be understood, however, that once the displacement piston (FIG. 4) has been lowered sufficiently to cause a significant amount of liquid concentrate to overflow into the mixing compartment and has thereafter been re-elevated by the weighted float (i.e. upon the withdrawal of solution from the mixing compartment), the liquid remaining in the compartment 75 will (in the absence of replacement) fall below its original level. Once this begins to occur, however, the opening 256 will become fully uncovered, and a stream of small air bubbles will pass from this opening and through the orifice 255 into the upper reaches of the container 30. [n this way, the vacuum in the container will be broken, so that liquid may be released through the tubulation 252. This will continue until the liquid level in compartment 75 again reaches the midpoint of theopening 256, at which time air flow will cease and a new condition of stabilization will exist.

The liquid control system just described provides special advantages in avoiding large scale surges of inrushing air and out-rushing liquid at any time. That is to say, the succession of small air bubbles which develops in the restricted path formed by the

openings

256 and 255, taken in connection with the restricted liquid flow which can occur through tubulation 252, precludes the severe glugging" effect often encountered in vacuum-controlled liquid feed systems. This in turn prevents the occurrence of perturbations or fluctuations in liquid level in compartment 75 sufficiently violent to cause liquid concentrate to slop over the wall surface 75b (FIG. 4) and thus to produce unpredictable variations in the proportions of the solution formed in compartment 70. It is believed sufficient for operability in this fashion that the

openings

255 and 256 and the opening in tubulation 252 be specified as relatively small in proportion to the cross-section of the main passage within the cylinder 242. In a particular case good results have been obtained with a construction in which the cylinder 242 has an internal bore of about one inch, and the

openings

252, 255 and 256 measure one quarter inch, one quarter inch and three eighths inch, respectively.

While the invention has been described by reference to a specific embodiment, it will be understood that numerous variations may be made by those skilled in the art without department from the invention. For example, for special purposes, the float 80 may be separated into two independently floating parts, one of which controls the off-on function of the water supply and the other of which operates the lever arms and 165. Coordination of these functions will, of course, be maintained by the fact that the two float parts will move synchronously with the rising and falling of the water level in the tank compartment 70. [t is therefore intended in the appended claims to cover all modifications which fall within the ture spirit and scope of the invention.

What is claimed is the following:

I. Liquid mixing and distributing apparatus compris- A. a first compartment for receiving a primary liquid and having a combination therewith l. first liquid supply means having an on condition in which it can introduce primary liquid into the first compartment and an off condition in which introduction of further primary liquid into the first compartment is precluded;

2. a float in the first compartment which rises and falls with the level of primary liquid in that compartment;

3. a liquid supply control connected with said float and operative when the liquid in the first compartment falls to a predetermined minimum level to turn said first liquid supply means to its on condition and operative when the liquid reaches a predetermined maximum level to turn that supply means to its off condition; and

4. control means effective when the liquid level in the first compartment reaches its maximum level to cause the liquid in that compartment to flow into a use conduit and effective when the liquid level in the compartment reaches its minimum level to preclude further flow of such liquid into the use conduit, whereby under the joint action of said control means and the said liquid supply control, the liquid in said compartment will oscillate between its maximum and minimum levels;

B. A second compartment arranged in proximity to said first compartment for receiving a secondary liquid to be mixed in measured quantities with the primary liquid, said second compartment 1. having a point above which liquid contained in that compartment will overflow into the first compartment; and

2. being provided with secondary liquid supply means effective during use of the apparatus to maintain a constant minimum level of the secondary liquid in the second compartment;

C. a piston extending downwardly into the second compartment, said piston being movable vertically between a relatively elevated position in which it does not displace sufficient secondary liquid to cause such liquid to rise above the overflow point of the second compartment and a relatively depressed position in which it does displace sufficient secondary liquid to cause such liquid to rise above said overflow point and to flow into intermixing relationship with the liquid contained in the first compartment; and

D. means effective to move the piston towards its relatively elevated position as the liquid level in said first compartment falls and effective to move the piston towards its relatively depressed position as the liquid level in the first compartment rises.

2. Apparatus according to claim 1 in which the said piston moving means includes an operative connection between the said float in the first compartment and the said piston for lowering the piston as the float rises and vice versa.

3. Apparatus according to claim 2 in which the operative connection between the float and the piston comprises A. a lever articulated at one end to the float and articulated at the other end to the piston; and

B. a fulcrum for the lever located between its ends at a point such that downward movement of the float raises the piston and upward movement of the float produces lowering of the piston.

4. Apparatus according to claim 2 which further includes adjustable means for limiting the downward motion of the piston without regard to the maximum upward motion of the float, thereby to permit controlled variation of the quantity of secondary liquid overflowing into the primary liquid without concurrently altering the quantity of liquid supplied to the first compartment.

5. Apparatus according to claim 4 in which the said adjustable means includes a centrally pivoted lever which at one end has a part operative to interrupt the downward movement of the piston and which at the other end coacts with operator controllable means for adjusting the lever position thereby to vary the point of limitation of downward movement of the piston.

6. A solution mixing and distributing apparatus comprising A. a tank structure including 1. a first compartment for receiving a primary liquid,

2. a second compartment for receiving a secondary liquid to be admixed in measured quantities with the primary liquid, and

3. a wall portion separating the two compartments, said wall portion being impervious to liquid flow below a predetermined level, but above that level permitting flow of liquid from the second compartment to the first compartment;

B. first liquid supply means having an on condition in which it can introduce primary liquid into the first compartment and an off condition in which introduction of further primary liquid into the first compartment is precluded;

C. second liquid supply means effective during use of the apparatus to maintain a constant minimum level of the secondary liquid in the second compartment;

D. a float in the first compartment which rises and falls with the level of primary liquid in that compartment;

E. a liquid supply control connected with said float and operative when the liquid in the first compartment falls to a predetermined minimum level to turn said first liquid supply means to its on condition and operative when that liquid reaches a predetermined maximum level to turn that supply means to its off condition;

F. a piston dimensioned to interfit within the second compartment, said piston having 1. a first vertical position in which it is suspended wholly or largely above the second compartment, and

2. a second vertical position in which it extends downwardly within the compartment so as to cause a preselected volume of liquid contained within the second compartment to rise above the said predetermined level in respect to said wall portion of the compartment and to flow into an admixing relationship with the liquid contained in the first compartment; and

G. a linkage between the said float and the said piston effective to move the piston toward its said first vertical position as the liquid level in said first compartment falls and effective to move the piston towards its said second vertical position as the liquid level in the first compartment rises.

7. Apparatus according to claim 6 in which the first compartment and the second compartment are formed unitarily of a single homogeneous material.

8. Apparatus according to claim 7 in which the homogeneous material is a molded liquid-resistant plastic.

9. Apparatus according to claim 6 in which A. The said piston occupies only a portion of the transverse area of the second compartment; and

B. the second liquid supply means comprises an inverted liquid container suspended above the second compartment and having a downwardly directed outlet conduit which extends into the second compartment 1. in a transverse region of the compartment which is not occupied by the said piston, and- 2. to a point below the surface level of secondary liquid which is normally to be maintained in the compartment.

10. Liquid mixing and distributing apparatus comprising A. a first compartment for receiving a primary liquid and having in combination therewith 1. first liquid supply means having an on condition in which it can introduce primary liquid into the first compartment and an off condition in which introduction of further primary liquid into the first compartment is precluded;

2. means responsive to changes in the level of primary liquid in that compartment;

3. a liquid supply control connected with said lastmentioned means and operative when the liquid in the first compartment falls to a predetermined minimum level to turn said first liquid supply means to its on condition and operative when the liquid reaches a predetermined maximum level to turn that supply means to its off condition; and

secondary liquid to cause such liquid to rise above said overflow point and to flow into intermixing relationship with the liquid contained in the first compartment; and

D. means effective to move the piston towards its relatively elevated position as the liquid level in said first compartment falls and effective to move the piston towards its relatively depressed position as the liquid level in the first compartment rises. =0 i

Claims

1. Liquid mixing and distributing apparatus comprising A. a first compartment for receiving a primary liquid and having a combination therewith 1. first liquid supply means having an on condition in which it can introduce primary liquid into the first compartment and an off condition in which introduction of further primary liquid into the first compartment is precluded; 2. a float in the first compartment which rises and falls with the level of primary liquid in that compartment; 3. a liquid supply control connected with said float and operative when the liquid in the first compartment falls to a predetermined minimum level to turn said first liquid supply means to its on condition and operative when the liquid reaches a predetermined maximum level to turn that supply means to its off condition; and 4. control means effective when the liquid level in the first compartment reaches its maximum level to cause the liquid in that compartment to flow into a use conduit and effective when the liquid level in the compartment reaches its minimum level to preclude further flow of such liquid into the use conduit, whereby under the joint action of said control means and the said liquid supply control, the liquid in said compartment will oscillate between its maximum and minimum levels; B. A second compartment arranged in proximity to said first compartment for receiving a secondary liquid to be mixed in measured quantities with the primary liquid, said second compartment 1. having a point above which liquid contained in that compartment will overflow into the first compartment; and 2. being provided with secondary liquid supply means effective during use of the apparatus to maintain a constant minimum level of the secondary liquid in the second compartment; C. a piston extending downwardly into the second compartment, said piston being movable vertically between a relatively elevated position in which it does not displace sufficient secondary liquid to cause such liquid to rise above the overflow point of the second compartment and a relatively depressed position in which it does displace sufficient secondary liquid to cause such liquid to rise above said overflow point and to flow into intermixing relationship with the liquid contained in the first compartment; and D. means effective to move the piston towards its relatively elevated position as the liquid level in said first compartment falls and effective to move the piston towards its relatively depressed position as the liquid level in the first compartment rises.

2. being provided with secondary liquid supply means effective during use of the apparatus to maintain a constant minimum level of the secondary liquid in the second compartment; C. a piston extending downwardly into the second compartment, said piston being movable vertically between a relatively elevated position in which it does not displace sufficient secondary liquid to cause such liquid to rise above the overflow point of the second compartment and a relatively depressed position in which it does displace sufficient secondary liquid to cause such liquid to rise above said overflow point and to flow into intermixing relationship with the liquid contained in the first compartment; and D. means effective to move the piston towards its relatively elevated position as the liquid level in said first compartment falls and effective to move the piston towards its relatively depressed position as the liquid level in the first compartment rises.

2. to a point below the surface level of secondary liquid which is normally to be maintained in the compartment.

2. a second vertical position in which it extends downwardly within the compartment so as to cause a preselected volume of liquid contained within the second compartment to rise above the said predetermined level in respect to said wall portion of the compartment and to flow into an admixing relationship with the liquid contained in the first compartment; and G. a linkage between the said float and the said piston effective to move the piston toward its said first vertical position as the liquid level in said first compartment falls and effective to move the piston towards its said second vertical position as the liquid level in the first compartment rises.

3. a wall portion separating the two compartments, said wall portion being impervious to liquid flow below a predetermined level, but above that level permitting flow of liquid from the second compartment to the first compartment; B. first liquid supply means having an on condition in which it can introduce primary liquid into the first compartment and an off condition in which introduction of further primary liquid into the first compartment is precluded; C. second liquid supply means effective during use of the apparatus to maintain a constant minimum level of the secondary liquid in the second compartment; D. a float in the first compartment which rises and falls with the level of primary liquid in that compartment; E. a liquid supply control connected with said float and operative when the liquid in the first compartment falls to a predetermined minimum level to turn said first liquid supply means to its on condition and operative when that liquid reaches a predetermined maximum level to turn that supply means to its off condition; F. a piston dimensioned to interfit within the second compartment, said piston having

3. Apparatus according to claim 2 in which the operative connection between the float and the piston comprises A. a lever articulated at one end to the float and articulated at the other end to the piston; and B. a fulcrum for the lever located between its ends at a point such that downward movement of the float raises the piston and upward movement of the float produces lowering of the piston.

3. a liquid supply control connected with said last-mentioned means and operative when the liquid in the first compartment falls to a predetermined minimum level to turn said first liquid supply means to its on condition and operative when the liquid reaches a predetermined maximum level to turn that supply means to its off condition; and

4. control means effective when the liquid level in the first compartment reaches its maximum level to cause the liquid in that compartment to flow into a use conduit and effective when the liquid level in the compartment reaches its minimum level to preclude further flow of such liquid into the use conduit, whereby under the joint action of said control means and the said liquid supply control, the liquid in said compartment will oscillate between its maximum and minimum levels; B. A second compartment arranged in proximity to said first compartment for receiving a secondary liquid to be mixed in measured quantities with the primary liquid, said second compartment

6. A solution mixing and distributing apparatus comprising A. a tank structure including

9. Apparatus according to claim 6 in which A. The said piston occupies only a portion of the transverse area of the second compartment; and B. the second liquid supply means comprises an inverted liquid container suspended above the second compartment and having a downwardly directed outlet conduit which extends into the second compartment

10. Liquid mixing and distributing apparatus comprising A. a first compartment for receiving a primary liquid and having in combination therewith