US3913797A

US3913797A - Fluid dispensing system

Info

Publication number: US3913797A
Application number: US441101A
Authority: US
Inventors: Stanley J Brym
Original assignee: Baldwin Gegenheimer Corp
Current assignee: Baldwin Gegenheimer Corp
Priority date: 1974-02-11
Filing date: 1974-02-11
Publication date: 1975-10-21
Anticipated expiration: 1992-10-21
Also published as: DE2504572C2; GB1476052A; DE2504572A1; JPS5824276B2; IT1024941B; FR2260394B1; FR2260394A1; JPS50117507A

Abstract

For delivery of cleansing liquid to printing rollers, a collapsible chamber is incompletely filled with a liquid which is thereafter delivered directly to spray nozzles by compression of the chamber. Reexpansion of the chamber draws in a new charge of liquid and concurrently withdraws residual liquid from the spray orifices to prevent dripping on the cleaned printing rollers. A two chamber system is disclosed in which a new charge of cleaning liquid is received in and metered by a first chamber for subsequent transfer to the second chamber.

Description

United States Patent [1 1 Brym [ Oct. 21, 1975 [54] FLUID DISPENSING SYSTEM [75] Inventor:

[73] Assignee: Baldwin-Gegenheimer Corporation,

Stamford, Conn.

22 Filed: Feb.1l, 1974 [21] Appl. No.: 441,101

Stanley J. Brym, Torrington, Conn.

3,806,084 4/1974 Seese 222/571 X Primary Examiner-Robert B. Reeves Assistant ExaminerLarry H. Martin Attorney, Agent, or FirmSt. Onge Mayers Steward &

Reens [57] ABSTRACT For delivery of cleansing liquid to printing rollers, a collapsible chamber is incompletely filled with a liquid which is thereafter delivered directly to spray nozzles by compression of the chamber. Reexpansion of the chamber draws in a new charge of liquid and concurrently withdraws residual liquid from the spray orifices to prevent dripping on the cleaned printing rollers. A two chamber system is disclosed in which a new charge of cleaning liquid is received in and metered by a first chamber for subsequent transfer to the second chamber.

7 Claims, 3 Drawing Figures US. Patent Oct. 21, 1975 Sheet10f2 3,913,797

US. Patent Oct.21,1975 Sheet 2 of2 3,913,797

Q3 Q? Q E. $8

1 mun DISPENSING svs'rsm BACKGROUND OF THE INVENTION AND SUMMARY This invention relates to a fluid dispensing system and more particularly to liquid dispensing apparatus which is especially adapted for use as a cleansing accessory for the ink-bearing rolls of a printing press.

A general approach to the intermittent cleaning of printing rollers is described in US. Pat. No. 2,970,541, issued Feb. 7, l96l in the name of Harold W. Gegenheimer. This patent discusses, for example, spraying a liquid solvent on the rollers to be cleaned, and following this by application of a wiping blade to the roller surfaces to remove the dissolved ink and the residual solvent. In further developments of this procedure, use has been made of a fixed array of spray noules for conveniently applying solvent to an extended area of the printing roller desired to be treated at a given time. This otherwise desirable and convenient approach has, however, introduced the possibility of unwanted dripping of residual solvent retained in the spray nozzles after the wiping phase of the cleansing operation has been completed. Such dripping, when it occurs, may deposit pools of solvent on the ostensibly clean roller surfaces, with resulting harmful effects on subsequent printing operations.

It has been recognized that one cure for this problem lies in positively terminating the supply of solvent to the spray nozzle orifices at the end of the spraying cycle. Specific means to this end have been described in US. Pat. No. 3,508,711, issued Apr. 28, i970 in the name of T. G. Switall. The means proposed by this patent comprise a set of spring-seated needle valves, each member of the set being associated with a specific spray nozzle and being closed except in the presence of pressurized solvent in the solvent supply line which connects with the nozzle assembly. Solvent pressure in the supply line is in turn controlled by an appropriate valving system. Thus, one specifically described control arrangement comprises an air-actuated bellows which in the air-on condition channels pressurized solvent to the nozzle valves, forcing them open, and which, in the air-off" condition, terminates the flow of solvent and at the same time relieves pressure in the nozzle supply line sufficiently to permit the individual nozzle valves to close.

While the system just described affirmatively prevents any substantial continuing leakage of solvent from the various nozzles, it does not preclude single droplets from being formed by the small residue of solvent which may be retained at each nozzle opening even afier the supply of solvent is terminated. Because even a single such droplet, falling on a critical area of a printing roller, may produce a printing defect, still further safeguarding measures are found desirable.

The present invention solves this residual problem by providing means by which, at the end of each solvent supplying cycle, a negative pressure" is developed at the supply line side of each spraying orifice, thus drawing back into the orifice (and eventually into the supply line) any lingering quantities of solvent which may occupy or surround the orifice opening. In a preferred embodiment of the invention this result is accomplished by the provision of a fluid dispensing system in which both the positive pressure needed to accomplish spraying action and the negative pressure needed to draw back into the system residual orifice droplets are produced directly by on-off control of a supply of pressurized solvent.

DETAILED DESCRIPTION Further and more detailed aspects of the invention will be made apparent by reference to the following specification taken in connection with the appended drawings.

In the drawings:

FIG. 1 is a view, partly in true cross-section and partly schematic, of a fluid dispensing system in accordance with the invention;

FIG. 2 is a sectional view of the principal functional elements of FIG. 1 shown in an altered operating condition; and

FIG. 3 is a schematic representation of an exemplary control circuit for use with the system of FIG. 1.

In FIG. 1 there is shown schematically a liquid dispensing system which comprises a source 10 of pressurized liquid and, at the right hand end of the Figure, an outlet nozzle 15 having an orifice through which liquid from the source is desired to be projected in a controllable fashion. In the printing press application with which the invention is principally concerned the liquid source 10 may comprise a tank of cleansing solvent (for example, a petrochemical derivative) which is maintained under pressure as by a compressed air source (not shown) associated with the tank. In the same application, the nozzle 15 may be one of several similar nozzles connecting with a manifold 17. This manifold, which is shown in section, may be assumed to have considerable extension in its axial direction and to carry along its length of series of spaced nozzles corresponding in form and function to the nozzle 15.

In proximity to the nozzle 15 there is shown in end view a segment 20 of what may be taken to be an inking roller. As will be readily understood, such a roller in its normal usage tends to acquire surface accumulations of ink which must be removed from time to time by a cleansing operation. In this context it is the function of the nozzle 15 (and of the similar additional nozzles associated with the manifold 17) to spray a cleansing solvent on the roller surface at times and during periods which may be selected by the operator of the printing equipment. In connection with the roller 20 there is further shown a wiping blade 25 which, under the control of the equipment operator, may be moved into contact with the surface of the roller in order to scrape from it the mixture of solvent and dissolved ink which results from a spraying operation. The removed substances are collected in a trough 27 from which they may be disposed of by any suitable means. A complete roller cleaning system employing cleaning elements such as those just referred to is fully disclosed in US. Pat. No. 2,970,541, previously referred to herein and hereby incorporated by reference in the present specification.

As has been indicated, spraying and wiping procedures are now widely used in the printing art. As has been further stated, however, these procedures introduce the problem of after-cleansing drippage of solvent from spray nozzles as heretofore employed, with resultant harmful effects in subsequent printing operations. The aspects of FIG. 1 which have not so far been described a new form Of flow control apparatus which is to be interposed in the conduit system extending between the source and the spray orifice a for controlling the fiow of liquid through the conduit system in a fashion which will eliminate the drippage difficulty just referred to.

In general terms, the flow control apparatus employed by the present invention comprises the combination of means for alternatively establishing fiow of liquid from the source 10 to a conduit portion 30 which connects with the manifold 17 and through the manifold with the nozzle 15 and secondly, under control of an appropriate cycling device, interrupting such flow after a desired time interval. With the means just described there is combined further means, effective upon interruption of liquid flow to the manifold 17 to establish a negative pressure within the conduit portion 30 thereby to withdraw residual liquid from the orifice of the spray nozzle 15. (The term negative pressure is here used in the broadest sense to mean not only a pressure which is sufficiently below atmospheric pressure to produce in-draft of air through the nozzle orifice but also any pressure which is reduced sufficiently below a pre-existing pressure to induce or permit positive inflow of fluid through the spray orifice whether under the influence of air pressure, gravity or otherwise).

In the specific embodiment which is illustrated in FIG. 1, the control means described generally in the preceding paragraph comprises a coupled piston as sembly designated generally by the numeral 35. This assembly is shown in longitudinal cross-section, but as seen end-on, would appear as of generally cylindrical configuration. Thus, it includes disk-

like end plates

37 and 38 which are joined by a set of symmetrically disposed tie rods 40, of which only two are shown. Compressively retained between the end plates in end-toend relation are a first cylinder 42 and a second cylinder 44, the latter being of significantly larger diameter than the former. The

cylinders

42 and 44 are separated at their most nearly abutting extremities by a circular plate 46 upon which each cylinder bears circularly as indicated at 48 and 50, respectively. Centrally disposed within the cylinder 42 there is a smaller piston-forming cylinder 52 which terminates at its left hand in a circular cylinder head 54. Extending across the outer surface of the cylinder head is flexible roll-up diaphragm 56 which may consist of fabric having a solventresistant impregnation and the function of which will be further described at a later point. In the illustrated position of the piston cylinder 52 the diaphragm S6 extends across the head of the piston then loops back upon itself in the annular space provided between the

cylinders

42 and 52 as indicated at 56a. It terminates peripherally in an enlarged bead 56b which is compressively retained between the end plate 37 and an annular ring 58 which also provides a centering retaining means for the cylinder 42. A circular cover plate 60 which has a screw threaded attachment 62 to other parts of the piston structure compressively engages the central area of the diaphragm 56, holding it firmly against the outer surface of the cylinder head 54. As will appear at a later point, the space between the end plate 37 and the facing surface of the diaphragm 56 provides a collapsible (and extensible) chamber, the volume of which may be varied by movement of the piston cylinder 52 for purposes subsequently to be described.

Extending axially of the piston cylinder 52 is a connecting rod 65 which is secured to the cylinder end wall 54 by means of the threaded screw 62. This connecting rod extends through the dividing wall 46, being slidably supported in the central portion of that wall by means of a bushing 70. To the right of the wall 46 the connecting rod occupies an axial position within a second piston cylinder 75, which is terminated at its right hand end by a cylinder head held in place by attachment to the abutting extremity of the connecting rod 65. Attached to the outer surface of the cylinder head is a flexible roll-up diaphragm 83 which in turn is clamped against the cylinder head by a circular cover plate 84 held in place by the screw threaded member 86. The diaphragm 83 is similar in construction to the diaphragm 56, previously described, and, like that diaphragm, terminates at its peripheral edge in an enlarged beaded portion 83b. As shown, this beaded portion is held against the circular end wall 38 by a grooved clamping ring 90. The entire structure as so far described is held in demountable assembly by the tie rods 40, previously referred to.

In considering the operation of the control apparatus, it needs to be noted that the end plate 37 has an inletoutlet port by which liquid may be admitted to and withdrawn from the otherwise generally sealed space bounded by the flexible diaphragm 56. Similarly, the opposite end wall 38 has an inlet-outlet port 99 by which liquid may be admitted to and withdrawn from the space bounded by the second diaphragm 83. It is also important at this point to note that the volumetric space contained within the diaphragm 83 in the fully expanded condition in which it is shown in FIG. 1, significantly exceeds the corresponding volumetric space within the diaphragm 56 in the fully expanded condition in which it is shown in FIG. 2. The latter observation makes it appropriate to consider next the operational steps and the practical results (in terms of utility of the invention) which are involved in changing the apparatus from the condition shown in FIG. 1 to that shown in FIG. 2. In this connection attention is first directed to the two-position slide valve illustrated schematically in both FIGS. 1 and 2. This is shown (again schematically) as comprising an outer sleeve 1100 within which is slidably mounted a twochambered, closed-end cylinder 11%. For convenient subsequent reference the two chambers of the cylinder are separately labelled A and B. It will be seen that in the position of the cylinder 11% which is represented in FIG. I, passage of liquid from the pressurized liquid source 10 is effectively blocked. In this circumstance, however, chamber B provides a connection between the port 95 which communicates with the interior of diaphragm 56 and port 99 which communicates with the interior of diaphragm 83. This connection is created by a conduit system which includes a tubular connection extending between the port 95 to a port 122 in valve chamber B, thence through port 124 in valve chamber B to a further tubulation 126 which connects at its opposite extremity 126a with port 99 formed in end wall 38. It needs to be observed at this point for further reference at a later stage that the tubulation 126 also has a direct connection through the branch tubulation 30 with the mainfold 17 and through this and through the connecting nozzle 15 with the orifice 15a out of which solvent liquid is eventually to be projected.

Let it now be assumed that by means to be explained at a later point a quantity of solvent liquid has previously been introduced into the space within the diaphragm 83 as indicated at 130. Note also at this point that the two-chambered valve cylinder 110b is movable axially under the joint control of a tension spring 135 and a solenoid shown diagrammatically as comprising a magnetic core or plunger 138 and an energizing coil 139. In the condition of the apparatus illustrated in FIG. I, solenoid coil 139 assumed to be de-energized, but it is further assumed that its terminals 140 are connected to a source of possible energization (see FIG. 3). Under these circumstances if energization is now applied to the terminals 140, the valve cylinder ll0b will be drawn to the right by the solenoid, as shown in FIG. 2, and the

ports

145 and 146 of valve chamber A will establish direct connection between tubulation a leading from the pressurized liquid source 10 and tubulation 120 leading to the port 95 which communicates with the interior of the diaphragm 56. At the same time the left hand end of the tubulation 126 will be cut off from communication with tubulation 120. In these circumstances, pressurized liquid will enter the space bounded by the diaphragm 56 and, in due course, will move the piston cylinder 52 into the position which it is shown to occupy in FIG. 2. In so doing it will, among other things, overcome the opposing force of compression spring 150 and will cause that spring to store potential energy for performance of a further function to be described at a later point. Because compression of the spring 150 tends to produce an objectionable twisting motion of the parts with which the spring is associated (necessarily including the diaphragm 56), the right hand end of the spring is provided with an antifriction thrust bearing assembly 155 which permits that end of the spring to rotate freely, thus eliminating the application of torsional force to the diaphragm. Secondly, right hand motion of the piston cylinder 52 will produce corresponding motion of the connecting rod 65 and identical motion of the piston cylinder 75 and the associated cylinder head 80. As suggested by FIG. 2, this will produce compression of the space within the diaphragm 83, the degree of compression being determined by the location of the abutment 160, which may be made adjustable as shown to accommodate differing circumstances of operation. Attention is directed to the fact that air holes 165 formed in the dividing plate 46 prevent entrapment of air in any of the interior spaces of the apparatus and thus preclude blockage of the piston action so far described.

It will readily be seen that the movement of parts just described will necessarily force into tubulation segment 1260 the body of liquid solvent 130 shown in FIG. 1 as being enclosed by the diaphragm 83. Moreover, since tubulation 126 is now closed at its left hand end (see FIG. 2) this liquid will necessarily be projected into the manifold 17 and thence through the nozzle and the orifice 15a. The resulting spraying action will continue until the stored liquid has been entirely expelled, or, in any event until the piston cover plate 84 reaches the limiting abutment 160. In this way a metered quantity of cleansing fluid is projected onto the surface of the inking roller 20 whence it will in due course be removed (along with dissolved ink) by action of the wiping blade 25. Because in normal usage a succession of spraying and wiping cycles are ordinarily employed, it is contemplated that the fluid control apparatus will be caused to perform its various operating functions a number of times during any given cleaning operation although this is not necessary for the useful application of the present invention. In any event, whether one or more spraying cycles is to be performed, the present invention contemplates that any given cycle will be terminated by de-energizing the solenoid coil 139, thus permitting the tension spring 135 to return the twochambered valve cylinder 1 10b to the position which it occupies in FIG. 1. Under these circumstances, the

valve ports

122 and 124 will again be opened, thus directly interconnecting the openings 99 and through the tubular connections and 126. Concurrently, the opening 95 will be disconnected from the pressurized liquid source 10. Because of the last-mentioned circumstance, the compression spring 150, acting within the piston cylinder 52, will be effective to move that cylinder to the left, thus compressing the diaphragm 56. By this operation the cleansing liquid b contained within the diaphragm-enclosed space will, as a first result, be forced through the

tubular connections

120, 126, and 126a and thence through the opening 99 into the chamber enclosed by the diaphragm 83 at the right hand end of the control apparatus. Because, as has been previously explained, this chamber is significantly larger than the corresponding chamber enclosed by the diaphragm 56, the full expansion of diaphragm 83 (i.e. to the position shown in FIG. 1) will in effect draw a vacuum in that chamber which can only be filled by the in-draft of air through the nozzle 15. This action will be effective, regardless of the orientation of the nozzle, to draw back into the nozzle and thence into the conduit system any droplets or particles of solvent which might otherwise tend to accumulate in the vicinity of the orifice in a condition which could permit subsequent dripping onto critical surfaces of the printing equipment. While this drawing in of solvent is especially useful in the case in which the nozzle has a downwardly directed orientation, it is also useful regardless of the specific nozzle orientation which is employed. In some cases the nozzle orifice may be directed upwardly so that liquid collected on the lip of the orifice would have a natural tendency (i.e. under the influence of gravity) to flow back into the nozzle. Even in such a case, however, the present invention is still useful in that the mere lessening of the volume of liquid contained in by the

tubular portions

126 and 126a which is inherently accomplished by the invention will facilitate, by syphon effect and otherwise, the withdrawal of excess fluid from the vicinity of the orifice.

The apparatus construction of FIGS. 1 and 2 has a special advantage in that a single pressurized fluid (i.e. the cleansing solvent itself) serves both as the means for compressing the piston represented by the cylinder 52 and for supplying solvent to the spray nozzle manifold 17. It will be understood, however, that, if desired for any reason, a separate source of energization of the piston cylinder 52 may be employed, such, for example, as a valve-controlled stream of pressurized air or other fluid medium. From this point of view, a primary requirement of the present invention is that the volume of the chamber represented by the fully expanded diaphragm 83 must be greater than the volume of solvent introduced into the conduit system when the diaphragm is compressed. Where this condition is met, reexpansion of the diaphragm under the influence of the compression spring will, provided there is unrestricted communication between the diaphragmenclosed chamber and the nozzle manifold (as illustrated, for example, in FIG. I), produce a negative pressure at the nozzle orifices, with the beneficial results previously described. For the achievement of the last-mentioned result, it is, of course, not essential that the discrepancy between the sizes of the two collapsible chambers be as great as that illustrated in FIGS. 1 and 2. Indeed, for particular purposes, and especially where low cost is vital, one may employ for purposes of the invention, the rod-end and head-end chambers of a typical double-acting piston cylinder in which the maximum rod-end volume is necessarily less than the maximum head-end volume by virtue of the space deducted from the former by the body of the rod itself.

In the arrangement of FIGS. 1 and 2, the function of introducing into the space enclosed by the diaphragm 83 a quantity of liquid which incompletely fills that space is accomplished in the following way. When the diaphragm 56 is fully expanded as shown in FIG. 2, it will of necessity be filled by a specific quantity of pressurized solvent which, as described above, is the cause of its expansion. Moreover, the volume of liquid 13Gb so contained is, by virtue of the specified relationship between the sizes of the two

diaphragms

56 and 83, significantly less than the expanded volume of the space enclosed by the latter diaphragm. Accordingly, when the solenoid coil 139 is de-energized so that the valve system is returned to the position shown in FIG. I, the action of the spring 150 will be to drive the measured quantity of solvent initially contained within the dia phragm 56 through the

tubulations

120, 126 and 126a and through the wall opening 99 into the relatively large chamber in the process of being formed by the expanded diaphragm 83. Thus, the partially filled condition of this chamber represented in FIG. 1 will be restored, the quantity of liquid received in the chamber being metered" in accordance with the dimensions of the diaphragm 56.

With the arrangement just described the cycle of the spray projection followed by recapture of residual solvent from the spray orifices can be repeated as many times as desired. Where a succession of spraying and wiping cycles is desired, this may be accomplished automaticaily by use of an appropriate timing mechanism. By way of illustration only, an exemplary timing mechanism is pictured diagrammatically in FIG. 3. In this Figure the terminals 140 of the solenoid coil 339 (FIG. 1] are shown as being connected to an eiectrical power source 180, the application of which is controlled by a switch 185. Closure of this switch initiates rotation of a low speed motor 190 which, in turn, rotates a con tact-bearing wheel 200. Electrically conductive members 205 spaced around the periphery of this wheel serve intermittently to interconnect conductors 210 and H5, thus cyclically energizing the coil 139. Any desired timing of the on and off portions of the switching cycle can be provided by appropriate spacing and dimensions of the contacts 205 and/or the speed of rotation of the output shaft of the motor 190. The switch 185 may also be electronically controlled to interlock the operation of the spraying mechanism with the apparatus which controls the rotation of the roller and the action of the wiping blade 25.

While the invention has been described by reference 6 such variations as fall within the true spirit and scope of the invention.

I claim:

1. In a press washer, a liquid dispensing system of the type which includes a source of liquid, an orifice through which such liquid is to be projected, and a conduit system extending between said source and said orifice for establishing a liquid-bearing connection between them to convey washing liquid to the press parts to be washed comprising,

A. control apparatus to be interposed in the conduit system, such apparatus comprising, 1. a first expansible and collapsible chamber for alternatively a. establishing flow of liquid from the source to the portion of the conduit system which connects with the orifice when said chamber is collapsed, and

b. a multi-position valve in the conduit system for interrupting such flow, and

2. a second expansible and collapsible smaller chamber inter-connected to said first chamber to operate in opposite expanding or collapsing phase thereto, and being connected to the conduit system through said valve when said valve interrupts flow from said first chamber and effective upon such interruption of flow to establish a negative pressure within the portion of the conduit system which connects with the orifice, thereby to withdraw residual liquid from the orifice.

2. For use in a liquid dispensing system of the type which includes a source of liquid, an orifice through which such liquid is to be projected, and a conduit system extending between said source and said orifice for establishing a liquid-bearing connecting between then;

A. control apparatus to be interposed in the conduit system, such apparatus comprising 1. means for establishing flow of liquid from said source to a portion of the conduit system which connects with the orifice and for subsequently interrupting such flow, such means including a. an expansible and collapsible chamber,

b. means for introducing into the chamber in its expanded condition a metered volume of liquid less than the expanded volume of the chamber,

c. means for progressively collapsing the chamber and thereafter progressively re-expanding it, and

d. means operative during the progressive expat.

sion and contraction of the chamber for maintaining the chamber in direct communication with the said portion of the conduit system which connects with the orifice, whereby during the progressive collapsing of the chamber liquid may be projected through the orifice and during the progressive expansion of the charm ber residual liquid may be withdrawn f'om the orifice.

3. Control apparatus according to claim 2 in which the said means for progressively collapsing the said chamber comprises:

A. a second expansible and collapsible chamber which in its expanding phase operates to coilapse the first such chamber; and

B. control means for admitting to the second chamber pressurized fluid for expanding that chamber.

10 biased toward its non-collapsed condition and having a liquid-conveying connection with the said orifice, and

b. the smaller of the two chambers being normally biased toward its collapsed condition,

c. said two chambers being so interconnected that expansion of the larger chamber compresses the smaller chamber and vice versa, and

which may be introduced into the second chamber dur- 10 ing its expanding phase will be transferred as a metered liquid quantity into the first chamber during the second chambers collapsing phase.

6. Control apparatus according to claim 5 which fur- 2. multi-position valve means to be interposed between said pressurized liquid source and said chambers, said valve means a. being efi'ective in a first position thereof to perther includes multi-position valve means for altematively A. admitting liquid from said supply source to said second chamber for expanding it while maintaining that chamber out of connection with said first chamber, and

B. terminating admission of liquid to the second chamber to permit its collapse while establishing connection between that chamber and the first chamber, whereby the liquid content of the second chamber is transferred to the first chamber.

7. For use in a liquid dispensing system of the type which includes a source of pressurized liquid, an orifice to which such liquid is to be supplied, and a conduit system extending between said source and said orifice:

A. flow control apparatus to be interposed in the conduit system, such apparatus comprising 1. an assembly of two separately constituted collapsible chambers, one of which is of significantly greater internal volume than the other, a. the larger of the two chambers being normally mit delivery of pressurized liquid from the source to the smaller of the two chambers, thereby concurrently expanding that chamber and collapsing the larger chamber so as to impel toward the orifice any liquid contained in the larger chamber, and

b. being effective in a second position thereof to interconnect said first and second chambers while isolating both chambers from said pressurizled fluid source, whereby the concurrent expansion of the larger chamber and contraction of the smaller chamber which occurs under the influence of their normal biases i. transfers from the smaller to the larger of the chambers a metered amount of liquid corresponding to the decrease in volune of the smaller chamber, and

ii. produces in the larger chamber a net pressure decrease effective to withdraw residual liquid from the orifice connected to it.

i i I I i

Claims

1. In a press washer, a liquid dispensing system of the type which includes a source of liquid, an orifice through which such liquid is to be projected, and a conduit system extending between said source and said orifice for establishing a liquid-bearing connection between them to convey washing liquid to the press parts to be washed comprising, A. control apparatus to be interposed in the conduit system, such apparatus comprising, 1. a first expansible and collapsible chamber for alternatively a. establishing flow of liquid from the source to the portion of the conduit system which connects with the orifice when said chamber is collapsed, and b. a multi-position valve in the conduit system for interrupting such flow, and 2. a second expansible and collapsible smaller chamber interconnected to said first chamber to operate in opposite expanding or collapsing phase thereto, and being connected to the conduit system through said valve when said valve interrupts flow from said first chamber and effective upon such interruption of flow to establish a negative pressure within the portion of the conduit system which connects with the orifice, thereby to withdraw residual liquid from the orifice.

2. multi-position valve means to be interposed between said pressurized liquid source and said chambers, said valve means a. being effective in a first position thereof to permit delivery of pressurized liquid from the source to the smaller of the two chambers, thereby concurrently expanding that chamber and collapsing the larger chamber so as to impel toward the orifice any liquid contained in the larger chamber, and b. being effective in a second position thereof to interconnect said first and second chambers while isolating both chambers from said pressurized fluid source, whereby the concurrent expansion of the larger chamber and contraction of the smaller chamber which occurs under the influence of their normal biases i. transfers from the smaller to the larger of the chambers a metered amount of liquid corresponding to the decrease in volune of the smaller chamber, and ii. produces in the larger chamber a net pressure decrease effective to withdraw residual liquid from the orifice connected to it.

2. For use in a liquid dispensing system of the type which includes a source of liquid, an orifice through which such liquid is to be projected, and a conduit system extending between said source and said orifice for establishing a liquid-bearing connecting between them, A. control apparatus to be interposed in the conduit system, such apparatus comprising

3. Control apparatus according to claim 2 in which the said means for progressively collapsing the said chamber comprises: A. a second expansible and collapsible chamber which in its expanding phase operates to collapse the first such chamber; and B. control means for admitting to the second chamber pressurized fluid for expanding that chamber.

4. Control apparatus according to claim 3 in which the first chamber in its expanded condition has an enclosed volume significantly greater than the enclosed volume of the second chamber in its expanded condition.

5. Control apparatus according to claim 4 which further includes means effective during the collapsing phase of the second chamber to connect that chamber with the interior of the first chamber, whereby liquid which may be introduced into the second chamber during its expanding phase will be transferred as a metered liquid quantity into the first chamber during the second chamber''s collapsing phase.

6. Control apparatus according to claim 5 which further includes multi-position valve means for alternatively A. admitting liquid from said supply source to said second chamber for expanding it while maintaining that chamber out of connection with said first chamber; and B. terminating admission of liquid to the second chamber to permit its collapse while establishing connection between that chamber and the first chamber, whereby the liquid content of the second chamber is transferred to the first chamber.

7. For use in a liquid dispensing system of the type which includes a source of pressurized liquid, an orifice to which such liquid is to be supplied, and a conduit system extending between said source and said orifice: A. flow control apparatus to be interposed in the conduit system, such apparatus comprising