Actuating system and nozzles for liquid dispensers

An actuator system having a stationary circular array of mechanical devices. The actuator system includes two stationary motors: one motor to rotate the actuator implement around the circular array of mechanical devices until the desired mechanical device is reached; and a second motor to rotate the actuator implement into engagement with an actuator pin of the mechanical device. A nozzle includes a three-sided or U-shaped stationary enclosure, together with a movable gate that completes the enclosure and forms an adjustable size nozzle outlet. As the gate closes after a dispense is complete, a controlled flow of residual liquid exits the nozzle outlet to avoid any additional displacement, thus preventing the undesirable effect of liquid being squeezed out of the nozzle outlet as the gate closes. Conversely, when the gate opens, this sniff back action operates in reverse, thereby filling the nozzle outlet and preventing air from filling the nozzle.

BACKGROUND

Technical Field

This document discloses actuating systems and nozzles for liquid dispensers. More specifically, this document discloses actuating systems for a liquid dispenser that includes a stationary and circular array of nozzles. The disclosed actuating systems are capable of moving an actuator amongst or around the circular array of nozzles before the actuating system stops the actuator at a specific nozzle. The actuating systems then rotate the actuator to open the selected nozzle.

This document also discloses nozzles for multiple liquid dispensers that feature a slider that is movable between a fully closed position and a plurality of open positions, including a fully open position. The disclosed nozzles may be equipped with a sniff back function and a reverse sniff back function that keeps the nozzle full of liquid before, during and after the opening and closing of the nozzle.

Description of the Related Art

Systems for dispensing a plurality of different liquids into a container are known. For example, systems for dispensing paint base materials and colorants into a paint container are known. These paint dispensing systems may use twenty or more different colorants to formulate a paint mixture. Each colorant is contained in a separate canister or package and typically includes its own dispensing pump. In some systems, the colorants and the respective pumps may be disposed on a rotating turntable disposed above a stationary container. In other systems, the colorants may be disposed along one or more stationary horizontal rows disposed above a container disposed on moving platform. Also, in some systems, the colorants may be dispensed through a stationary dispense manifold into a stationary container, wherein the manifold includes a plurality of nozzles.

In a turntable system, the turntable rotates so that the liquid to be dispensed is moved to a position above a stationary container that is being filled. Turntable systems require at least one motor to rotate the turntable, another motor to open and close the nozzles associated with the liquids to be dispensed and separate motors to operate each liquid pump. Further, the motors operating each pump and the canisters containing the liquids are mounted for rotation with the turntable, resulting in a complex and somewhat cumbersome design.

In liquid dispensers using one or more stationary horizontal rows, the container moves laterally to the appropriate colorant/pump for the next dispense. A motor for opening and closing the nozzles associated with each liquid must travel with the container, which also makes for a cumbersome design.

In manifold designs, the container, liquid pumps, liquid canisters and nozzles remain stationary as the liquids are sequentially or simultaneously pumped though individual nozzles held closely together by a manifold block. However, as noted above, some liquid dispensers dispense more than 20 different liquids and it is difficult to design a manifold that can accommodate so many different nozzles in a space-efficient and compact manner. Further, nozzles disposed in manifolds are prone to clogging and dripping, both of which are problematic.

One way in which the precision of a liquid dispensing system is compromised is “dripping”. Specifically, a “leftover” drip may be hanging from a nozzle that was intended for a previous formulation and, with a new container in place under the nozzle, the drop of liquid intended for a previous formulation may be erroneously added to a new formulation. Thus, the previous container may not receive the desired amount of the liquid ingredient and the next container may receive too much.

To solve the drip problem, various scraper and wiper designs have been proposed to scrape any leftover material from an individual nozzle or an entire manifold block after a dispense operation is complete. However, these designs often require one or more different motors to operate the wiper element. Further, the use of a wiper or scraping function may not be practical in a multiple nozzle manifold design, as the liquids from the different nozzles will be cross-contaminated by the wiper or scraper, which would then also contribute to the lack of precision of subsequently produced formulations. Accordingly, improved nozzle designs that address the drip problem are needed.

Another problem associated with dispensing systems that make use of nozzles is clogging. Specifically, nozzle clogging may be experienced with the dispensing of relatively viscous liquids such as tints, colorants, base materials for paints and cosmetic products, certain pharmaceutical ingredients or other liquid materials having relatively high viscosities and/or volatile solvents. The viscous liquids have a tendency to dry and cake onto the end of the nozzles, thereby requiring frequent cleaning in order for the nozzles to operate effectively. For example, when a liquid or slurry material dries on a nozzle, the dispense stream may be misdirected causing the liquid or slurry to miss the container being filled. This problem is particularly prevalent in the dispensing of colorants or tints. While some mechanical wiping or scrapping devices are available, these devices are not practical for multiple nozzle manifold systems for the reasons set forth above and the scraper or wiper element must be manually cleaned anyway. Further, nozzles have also been known to clog entirely when exposed to air for an extended period, which renders wiping or scrapping devices ineffective.

Another problem associated with liquid dispensing systems is air entering the nozzle during the opening or closing of the nozzle. For example, when a nozzle is opened, air may be free to enter the nozzle outlet and consume some of the interior volume of the nozzle through which the liquid flows. Some dispensing systems may attempt to account for air in the nozzle during calibrations, but the results may be inconsistent. Other systems may require the nozzle to be primed with liquid before a dispense, which is time consuming and wasteful. Regardless, the presence of air in a nozzle compromises the accuracy of the dispense and improved nozzle designs are needed that address the air problem.

Nozzles for liquid dispensers of the type described above typically have two positions—open and closed. Because of the high degree of precision required by some applications, a nozzle design that can be opened fully or partly by a motorized mechanism would be very beneficial. Such a nozzle design would enable a fast dispense rate when in a fully open position and slower dispense rates when in partially open positions. Such an improved nozzle design would need to address the problem of air entering the nozzle between dispenses as well.

Accordingly, a need exists for improved multiple liquid dispensers and actuation systems that are less cumbersome and complex. A need also exists for improved nozzle designs that are not prone to clogging, that are not prone to allowing air into the nozzle between dispenses and that enable dispensing through the nozzle in not only a fully open position but through a plurality of partially open positions as well.

SUMMARY OF THE DISCLOSURE

In one aspect, the document discloses a method for opening and closing a nozzle outlet of a nozzle of a liquid dispenser without dripping liquid or drawing air into the nozzle. The nozzle includes a body having an interior space in communication with the nozzle outlet. The interior space provides an available volume for accommodating liquid. The nozzle outlet provides an outlet volume for accommodating liquid. The method may include:

charging the nozzle outlet and the interior space with liquid;

providing a volume compensator in liquid communication with the nozzle outlet and the interior space, the volume compensator configured to increase the available volume of the interior space when the nozzle is closed and the volume compensator further configured to decrease the available volume of the interior space when the nozzle is opened;

opening the nozzle outlet and decreasing the available volume of the interior space by a first amount about equal to an increase in the outlet volume at the nozzle outlet created by opening the nozzle outlet; and

closing the nozzle outlet and increasing the available volume of the interior space by a second amount about equal to a decrease in the outlet volume at the nozzle outlet created by closing the nozzle outlet.

In another aspect, this document discloses a nozzle for liquid dispenser. The nozzle may include a hollow nozzle body including a nozzle body inlet and an outlet body with a slider passageway extending therebetween. The outlet body may terminate at a U-shaped nozzle outlet. The nozzle outlet may include a distal wall disposed between two side walls. The nozzle may further include a slider including a slider body coupled to a gate. The slider body may be slidably accommodated in the slider passageway. The gate may be slidably accommodated in the outlet body and nozzle outlet. The gate may engage the distal wall and the two side walls of the nozzle outlet when the slider shifts to a fully closed position. The nozzle outlet may be in communication with the passageway as the slider and gate moves from the fully closed position to an open position. Further, the nozzle may include a volume compensating element in communication with the passageway that decreases an available volume in the passageway for accommodating liquid as the gate is opened and that increases the available volume in the passageway for accommodating liquid as the gate is closed.

In another aspect, an actuation system for a liquid dispenser is disclosed. The disclosed actuation system may include an indexer motor coupled to an indexer drive mechanism. The indexer drive mechanism may couple to indexer wheel. The indexer wheel may carry a final wheel. The final wheel may couple to an actuator transfer wheel. The actuator transfer wheel may coaxially couple for rotation with an actuator wheel. The actuator wheel may enmesh with an actuator drive mechanism. The actuator drive mechanism may couple to an actuator motor. And, the final wheel may carry an actuator implement.

In another aspect, a disclosed actuation system may include an indexer motor coupled to an indexer drive gear. The indexer drive gear enmeshes with an indexer gear. The indexer gear carries a final gear. The final gear enmeshes with an actuator transfer gear. The actuator transfer gear coaxially couples for rotation with an actuator gear. The actuator gear enmeshes with an actuator drive gear. The actuator drive gear couples to an actuator motor. Further, the final gear may carry or otherwise be coupled to an actuator implement.

In another aspect, a disclosed liquid dispenser may include a circular array of nozzles disposed on a stationary table. Each nozzle may be in communication with its own pump and its own canister of liquid. Each nozzle may also include an actuator pin movable between a fully open position and fully closed position. The indexer motor couples to an indexer drive gear. The indexer drive gear enmeshes with an indexer gear. The indexer gear carries a final gear for imparting circular motion to the final gear above the valves. The final gear enmeshes with an actuator transfer gear. The actuator transfer gear coaxially couples to the actuator gear for rotation with an actuator gear. The actuator gear enmeshes with an actuator drive gear. The actuator drive gear couples to the actuator motor. Further, the final gear may carry or otherwise be coupled to an actuator implement.

In another aspect, a disclosed liquid dispenser may include a stationary and circular array of nozzles, wherein each nozzle may be in communication with its own pump and its own canister of liquid. The dispenser may further include an actuation system that includes an indexer motor coupled to an indexer drive gear. The indexer drive gear enmeshes with an indexer gear. The indexer gear carries a final gear. The final gear in enmeshed with an actuator transfer gear. The actuator transfer gear coaxially couples to an actuator gear for rotation with the actuator gear. The actuator gear enmeshes with an actuator drive gear. The actuator drive gear couples to an actuator motor. The final gear carries an actuator implement. Each nozzle includes a hollow nozzle body including a nozzle body inlet, an outlet body and a nozzle body sidewall that extends therebetween. Each nozzle further includes a slider that includes a slider body coupled to a gate. Each outlet body includes an outlet body that slidably accommodates the gate of its respective slider. Each outlet body terminates at a nozzle outlet. Each outlet body includes a distal wall. Each gate includes at least one distal seal that sealably engages the distal wall of its respective outlet body when its respective slider shifts to a fully closed position. Each slider body sealably and slidably engages its respective nozzle body as each slider moves from the fully close position towards a fully open position or any one of a plurality of open positions.

In another aspect, yet another nozzle for a liquid dispenser may include a nozzle body including an inlet and an outlet. The nozzle body further includes a slider passageway for slidably accommodating a slider. The slider may include a gate. The slider body includes a reduced diameter portion that is disposed between the inlet and outlet when the slider is in an open position. The outlet includes a wall that engages the gate when the nozzle is in a closed position. The slider passageway is in communication with the outlet. The slider passageway accommodates a distal end of the slider when the slider is in the open position. Said distal end of the slider at least partially withdraws from the passageway when the slider moves towards a closed position. As a result, the movement of the slider partially out of the passageway as the nozzle is closed creates available volume and/or a low-pressure region in the passageway for receiving liquid from the outlet as the gate approaches and engages the wall of the outlet. Conversely, as the gate moves away from the wall of the outlet as the nozzle opens, available volume in the nozzle outlet is created for receiving liquid from the passageway. As a result, the nozzle outlet fills with liquid and presents a liquid surface that is flush with the nozzle outlet as the gate proceeds from a closed position to any open position, including but not limited to a fully open position.

In another aspect, another nozzle for a liquid dispenser includes a nozzle body including an inlet, an outlet and a passageway extending therebetween. The passageway slidably accommodates a slider. The slider includes a slider body coupled to a gate. The outlet slidably accommodates the gate and the outlet further includes a wall. The gate sealably engages the wall of the outlet when the slider shifts to a closed position. The nozzle body includes a chamber that at least partially accommodates the slider body when the slider is in an open position. The chamber is in communication with the outlet when the slider is in the open position. The slider body at least partially departs the chamber when the slider moves from the open position to a closed position thereby, thereby creating volume in the chamber for receiving liquid from the outlet as the gate is closed. Conversely, as the gate opens, available volume is created in the nozzle outlet and the available volume in the chamber is reduced as the slider body reenters the chamber. As a result, liquid flows from the chamber into the nozzle outlet, filling the nozzle outlet with liquid so the liquid continuously presents a liquid surface that is flush with the nozzle outlet as the gate opens.

In any one or more of the embodiments described above, the indexer wheel is an indexer gear, the indexer drive mechanism is an indexer drive gear enmeshed with the indexer gear, the actuator wheel is an actuator gear, the actuator drive mechanism is an actuator drive gear enmeshed with the actuator gear, the final wheel is a final gear, and the actuator transfer wheel is an actuator transfer gear enmeshed with the final gear.

In any one or more of the embodiments described above, the indexer wheel is an indexer pulley, the indexer drive mechanism is an indexer drive pulley coupled to the indexer pulley by a first endless belt, the actuator wheel is an actuator pulley, the actuator drive mechanism is an actuator drive pulley coupled to the actuator pulley by a second endless belt, the final wheel is a final pulley, and the actuator transfer wheel is an actuator transfer pulley coupled to the final pulley by a third endless belt.

In any one or more of the embodiments described above, the indexer gear is disposed coaxially between the actuator gear and the actuator transfer gear.

In any one or more of the embodiments described above, the indexer motor and the actuator motor are linked to a controller.

In any one or more of the embodiments described above, the indexer motor and the actuator motor are stepper motors.

In any one or more of the embodiments described above, the indexer motor and the actuator motor are mounted on a platform disposed above the actuator gear and opposite the actuator gear from the indexer gear.

In any one or more of the embodiments described above, the actuator transfer gear and the final gear are disposed below the indexer gear and opposite the indexer gear from the actuator gear.

In any one or more of the embodiments described above, the actuator implement couples to an underside of the final gear and extends vertically downward therefrom.

In any one or more of the embodiments described above, the indexer gear includes indicia that are readable by an indexer gear sensor. The indicia indicate a position of the indexer gear with respect to a zero position. The indexer gear sensor links to the controller.

In any one or more of the embodiments described above, the nozzle body and outlet body are separate components and the nozzle body includes a nozzle body outlet and the outlet body includes a collar that is sealably and mateably received in the nozzle body outlet.

In any one or more of the embodiments described above, the slider body is hollow and includes a slider body inlet, a slider body outlet and a slider body sidewall extending therebetween. The slider body sidewall couples to the actuator pin.

In any one or more of the embodiments described above, the collar of the outlet body includes an inner surface that mateably, sealably and slidably receives the slider outlet. Further, the collar of the outlet body includes an outer surface that is mateably and sealably received in the nozzle body outlet.

In any one or more of the embodiments as described above, the gate includes at least one proximal seal that sealably and slidably engages the inner surface of the collar as the slider slides towards the fully closed position.

In any one or more of the embodiments as described above, the slot in the nozzle body sidewall is elongated to permit the actuator pin and the slider to be slid from a fully open position where communication is established between the nozzle body inlet and the nozzle outlet to a fully closed position where engagement of the gate against the distal wall of the outlet body blocks communication between the nozzle body inlet and the nozzle outlet.

In any one or more of the embodiments described above, the slider is slidable to a plurality of open positions between the fully open position and fully closed position while maintaining sealing engagement between the slider body outlet and the collar of the outlet body.

In any one or more of the embodiments described above, the slider couples to a slider cover that is disposed exterior of the nozzle body. The slider cover engages a compensating member. The compensating member extends through an opening in the nozzle body. The slider cover pulls the compensating member at least partially out of the nozzle body as the slider moves towards the fully closed position and the slider cover pushes the compensating member into the nozzle body as the slider moves towards the fully open position.

In any one or more of the embodiments described above, the slider cover couples to the slider by the actuator pin.

The above features, functions, and advantages are achievable independently in various embodiments or may be combined in yet other embodiments, further details of which can be seen with reference to the following description and drawings.

The drawings are not necessarily to scale and that the disclosed embodiments are sometimes illustrated diagrammatically and in partial views. In certain instances, details are omitted which are not necessary for an understanding of the disclosed methods and apparatuses or which render other details difficult to perceive. Further, this disclosure is not limited to the particular embodiments illustrated herein.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

Turning first toFIG. 1, a dispenser30is disclosed which includes a stationary and circular array of nozzles31disposed on a table32. The array of nozzles31includes a plurality of individual nozzles33, each including an inlet34. Each nozzle33also includes an actuator pin35, the operation of which is explained below. The actuator pins35extend upward through a plate36that includes a plurality of guide slots37that permit the actuator pins35to move from a fully open position to a fully closed position and any of a plurality of open positions therebetween.

The actuator pins35are moved by the actuator system20, which may be applied to any array of mechanical devices as discussed below. In short, the actuator system20is not limited to the opening and closing of nozzles33, but may be used to actuate individual mechanical devices that are arranged in a circular array.

Returning toFIG. 1, a platform38disposed above the table32and the plate36. The platform38supports an indexer motor39and an actuator motor41. The indexer motor39couples to an indexer drive gear42. The indexer drive gear42enmeshes with an indexer gear43. The actuator motor41couples to an actuator drive gear44. The actuator drive gear44enmeshes with an actuator gear45.

The actuator gear45connects to an actuator transfer gear46that, as shown inFIG. 1B, enmeshes with a final gear47. The final gear47couples to or otherwise carries an actuator implement48athat, as discussed in greater detail below, is used to move the actuator pins35between various open positions and a fully closed position. The actuator implement48amay be in the form of a blade, fork or other structure that is appropriate for actuating the mechanical devices. In the example ofFIGS. 1A and 1B, the actuator implement48ais a blade, which is useful for individually engaging the actuator pins35. However, because the actuation system20is applicable to mechanical devices other than nozzles33, the structure of the actuator implement48amay vary, as will be apparent to those skilled in the art.

As shown schematicallyFIG. 1A, the indexer motor39and the actuator motor41link to a controller48. Further, the inlet34of each nozzle33connects to its own pump49that is in communication with its own canister51. The pumps49associated with each nozzle33also link to the controller48. The inlets34to the nozzles33extend radially outwardly and, accordingly, the disclosed nozzles33are disposed radially inwardly from the view ofFIG. 1Aand further extend downward through a central opening40(FIG. 2C) for depositing dispensed liquids into the container52shown inFIG. 1A. In the example shown inFIG. 2C, each nozzle33may include an outlet body54and/or a distal nozzle outlet55(see alsoFIG. 2D) that is directed downwardly as also illustrated inFIG. 1A.

Turning toFIG. 2A, the dispenser30may further include an indexer gear sensor56for detecting the position of the indexer gear43with respect to a zero reference position. Further, the dispenser30may include an actuator gear sensor56afor detecting the position of the actuator gear45with respect to a zero reference position. The indexer gear sensor56and actuator gear sensor56alink to the controller48. SeeFIG. 2Bfor another view of the indexer gear sensor56andFIG. 3for another view of the actuator gear sensor56a. As shown inFIG. 3, the flag or tab57may indicate a zero reference position for the indexer gear43and the tab57amay indicate a zero reference position for the actuator gear45.

FIGS. 4A-4Billustrate a spindle58about which the indexer gear43, actuator gear45and actuator transfer gear46rotate. As shown inFIGS. 4A-4Bthe spindle58also supports the platform38. The tabs57,57afor the sensors56,56aand the central opening40through which the nozzle outlets55extend are shown inFIG. 4A.

Referring toFIGS. 1A-1B and 2A-2B, in operation, the actuator implement48amoves to the selected nozzle33of the circular array of nozzles31by rotating the indexer gear43. To rotate the indexer gear43, the controller48activates the indexer motor39and an instruction from the controller48causes the indexer motor39to rotate the indexer drive gear42the requisite number of rotations (or a partial rotation) to cause the indexer gear43to rotate about the spindle58until the final gear47and actuator implement48aare disposed radially outside of the selected nozzle33and its actuator pin35. In some embodiments, depending upon the design of the dispenser30, the actuator implement48amay be rotated about the spindle58from a position radially inside of the actuator pins35. Using the indexer gear sensor56and the zero point reference tab57, one skilled in the art will appreciate that the indexer gear43can be rotated so that the actuator implement48ais in position adjacent to a selected actuator pin35associated with a selected nozzle33. To keep the final gear47and the actuator implement48afrom rotating with respect to the indexer gear43as the indexer gear43rotates about the spindle58, the actuator transfer gear46must rotate with the indexer gear43because the actuator transfer gear46is enmeshed with the final gear47and the final gear47is tethered to the indexer gear43. If the actuator transfer gear46and actuator gear45are not rotated with the indexer gear43, the final gear47will rotate as it circles around the actuator transfer gear46, which may result in the actuator implement48ainadvertently engaging one or more actuator pins35. Therefore, once the actuator implement48ais positioned to rotate about the spindle58without engaging (unintentionally) any of the actuator pins35, that position may be held by rotating the actuator gear45and the actuator transfer gear46with the indexer gear43while the indexer gear43rotates to the selected nozzle33. Thus, to rotate the final gear47and the actuator implement48ato a nozzle33of choice without rotating the actuator implement48awith respect to the indexer gear43, the controller48sends a signal to the indexer motor39and the actuator motor41to impart an identical number of rotations to the indexer drive gear42and the actuator drive gear44(or the appropriate ratio if the gear ratio of the indexer gear43and the actuator gear45is not 1:1). Once the final gear47and actuator implement48areach the desired nozzle33, the final gear47and actuator implement48amay be rotated to open or close the actuator pin35of the selected nozzle33by the controller48sending a signal to the actuator motor41to impart the desired number of rotations to the actuator drive gear44which, in turn causes the actuator gear45and the actuator transfer gear46to rotate. Due to the engagement between the actuator transfer gear46and the final gear47, rotation of the actuator transfer gear46imparts rotation to the final gear47, thereby causing the actuator implement48ato rotate and either push and actuator pin35radially inwardly towards its fully closed position or pull the actuator pin35radially outwardly through a plurality of open positions towards the fully open position. Thus, by rotating the actuator motor41or the actuator drive gear44and the actuator gear45while holding the indexer motor39, indexer drive gear42and indexer gear43stationary, the resulting motion causes rotation of the final gear47and actuator implement48awhile the indexer gear43remains stationary. The sensor56aand tab57amay be used to identify the starting and ending positions of the actuator implement48aand the final gear47.

It will be noted that the dispenser30features a design where both motors39,41, along with various motors driving the pumps49remain stationary thereby avoiding problems with mounting the motors39,41on moving parts or platforms. Placing the motors39,41on moving platforms presents problems associated with cabling and providing power to the motors39,41.

It will also be noted that the indexer gear43, indexer drive gear42, actuator gear45, actuator drive gear44, actuator transfer gear46and final gear47may be wholly or partly replaced by a belt drive transmission.

FIGS. 5A-7Aillustrate one disclosed nozzle33. The nozzle33may include a nozzle body61including an inlet34(see alsoFIG. 1A), an outlet body54and a slider62(not visible inFIGS. 5A-6A; seeFIG. 7A). The nozzle body61and outlet body54may be unitary in structure. As shown inFIG. 7A, the nozzle body61includes an inlet34and an outlet63with a through passageway extending therebetween. The nozzle body61further includes a sidewall64that includes a slot65. The slot65accommodates the actuator pin35that couples to the slider62. The slider62may include a slider body66that may be cylindrical (or somewhat cylindrical) or that may include an inlet67and an outlet68. The outlet68of the slider body66connects to a gate69. The gate69is slidably received in the outlet body54. The outlet body54may connects to a collar72that is mateably received in the outlet63of the nozzle body61if the two parts are not unitary. Further, the collar72may mateably receive the outlet68of the slider body66as shown inFIG. 7A.

InFIG. 7A, the slider62or gate69is in the fully open position. Liquid may enter the nozzle33through the inlet34of the nozzle body61and proceed through the inlet67of the slider body66before proceeding through the outlet68of the slider body66before entering the outlet body54and exiting the nozzle33through the nozzle outlet55. In the open position shown inFIG. 7A, a through passageway71is established between the inlet34and the nozzle outlet55.

Still referring toFIG. 7A, when the slider62is moved to the closed position (to the left inFIG. 7A), liquid disposed at or inside of the nozzle outlet55is squeezed or drawn upward into the outlet body54by the action of the gate69approaching the distal wall73in combination with the action of the slider body66and slider body inlet67moving away from the nozzle inlet34. As the gate69engages the distal wall73and the slider body66moves left inFIG. 7A, liquid is sucked from the nozzle outlet55and directed towards and through the slider body inlet67and into the nozzle body61or through passageway71. This sucking or sniff back action occurs because the “available volume” inside the nozzle body61increases as the slider body66moves to the left inFIG. 7A, or towards the outlet body54. By designing the nozzle body61, slider62and outlet body54in this way, a built-in sniffback feature is provided which eliminates the problem of a droplet disposed at the nozzle outlet55being pushed out of the nozzle outlet55and into the container52(FIG. 1A). Instead, any lingering liquid at the nozzle outlet55is sucked upwards into the nozzle33as the nozzle33is closed. Importantly, a reverse phenomenon occurs when the nozzle33ofFIGS. 5A-7Ais opened.

Specifically, as the nozzle33is opened by moving the gate69away from the distal wall73, liquid disposed in the through passageway71is drawn towards the nozzle outlet55because the available volume at the nozzle outlet55increases and the available volume in the through passageway71decreases as the slider body66moves towards the inlet34and farther into the nozzle body61. Further, the increase in available volume at the nozzle outlet55is equal to or about equal to the decrease in volume experienced in the through passageway71as the slider body66moves back into the nozzle body61and towards the inlet34. By balancing these volumes, the reverse action that occurs when the nozzle33is opened prevents air from entering the nozzle outlet55as the gate69is opened. In addition, a fresh supply of liquid is disposed in the nozzle outlet55each time the gate69is opened. As a result, when the gate69is opened, a fresh supply of liquid is disposed inside the nozzle outlet55that presents a liquid surface that is flush or essentially flush with the nozzle outlet55. Therefore, each time the gate69is opened before a dispense, the nozzle outlet55or outlet body54is charged with liquid and not air. This action enhances the accuracy of the dispenser30because the nozzle33is always full of liquid without substantial pockets of air, which would compromise the accuracy of a volumetric dispense. Further, the flush liquid surface presented at nozzle outlet55is predictable and repeatable.

FIGS. 5B-7Billustrate another nozzle33b. The nozzle33bincludes a nozzle body61bincluding an inlet34b, an outlet55b, a slider passageway95a, a slider62b(seeFIG. 7B). The outlet55bincludes a distal wall173and a pair of side walls173b, only one of which can be seen inFIG. 5B. As shown inFIG. 7B, the nozzle body61bincludes a through passageway95bbetween the inlet34band the outlet55b. InFIG. 7B, the nozzle33bis in an open position with a reduced diameter portion62cof the slider62bdisposed in the passageway95bbetween the inlet34band the outlet55b. The slider62balso includes a gate69b. When the nozzle63bis closed, the slider62bis drawn to the left inFIG. 7Buntil the gate69bengages the wall73bof the outlet55b. This action expands the available volume of the chamber95cby an amount about equal to the volume of the chamber95dformed by the gate69band wall73bwhen the nozzle33bis in the open position. As a result, any liquid disposed at the outlet54bor in the chamber95dwhen the slider62bbegins a closing movement will be sucked up into the chamber95cas opposed to being squeezed out of the nozzle33bor out of the nozzle outlet55b. Accordingly, like the nozzle33ofFIGS. 5A-7A and 8-24, the nozzle33balso includes a built-in sniff back function. Further, when the nozzle33bis opened, the available volume in the chamber95cshrinks as the gate69bmoves from a position against the wall73bto the position shown inFIG. 7B. This action causes liquid in the chamber95cto flow into the nozzle outlet55bto form a supply of liquid in the nozzle outlet55bthat presents a surface that is flush with the nozzle outlet55b.

Turning toFIGS. 8-14, details of the slider62of the nozzle33are illustrated. Beginning withFIG. 8, the slider body66includes a groove81disposed near the inlet67for accommodating the seal member78(seeFIG. 7) and the groove82near the outlet68for purposes of accommodating the seal member77(seeFIG. 7). At least one opening83may be disposed in the slider body66for accommodating the actuator pin35. For structural stability purposes, two openings83may be diametrically oppositely disposed in the sidewall84of the slider body66as illustrated inFIG. 7. Turning to the gate69, the groove85accommodates the seal member74and the groove86accommodates the seal member75.

FIGS. 15-17illustrate details of the nozzle body61of the nozzle33. The legs88may secure the nozzle body61and the nozzle33to the table32as illustrated inFIGS. 2C-2D. Details of the outlet body54are provided inFIGS. 18-24. The reader will note, fromFIG. 22, that there is no proximal wall opposite the nozzle outlet55from the distal wall73. Such a structure is not necessary as the seal members76,77and the engagement of those seal members76,77with the collar72of the outlet body54prevent liquid from leaking beneath the gate69of the slider62.

FIGS. 25-27illustrate three additional nozzles133,233,333respectively that also balance available volumes for receiving liquid when the nozzles are opened and closed. InFIG. 25, the nozzle133includes a stationary nozzle body161that includes or connects to an inlet134. An outlet body154forms part of the nozzle body161as shown inFIG. 25. The outlet body154includes a distal wall173and two sidewalls that are not shown. The nozzle body161accommodates a slider162that couples to an actuator pin135. The actuator pin135couples the slider162to a slider cover91. The slider cover91slides along the nozzle body161with the slider162. The slider cover91passes through a compensating member92or, more specifically, a cammed slot93in the compensating member92.

To move the slider162from the open position shown inFIG. 25to a closed position where the gate169engages the distal wall173of the outlet body154, the actuator pin135shifts to the left inFIG. 25. Leftward movement of the slider162results in the gate169engaging the distal wall173and further results in the slider cover91shifting to the left and causing the compensating member92to be raised upward or in the direction of the arrow94. By withdrawing a portion of the compensating member92from the nozzle body161as the nozzle133is closed, liquid near of the nozzle outlet155will be drawn towards the available volume created by the withdrawing compensating member92. As a result, any drop or residual liquid disposed at or near the nozzle outlet155upon closure of the slider162results in that liquid being drawn upward into the through passageway95, thereby avoiding any dripping of liquid after the slider162is shifted to a closed position. Conversely, when the nozzle133is opened, the gate169moves away from the wall173thereby increasing the available volume at the nozzle outlet155. Further, as the piston cover91moves to the right inFIG. 25, the engagement of the cammed slot93and the piston cover91causes the compensating member92to drop downward and into the passageway95, thereby causing liquid to fill the nozzle outlet155. By balancing the loss of volume at the nozzle outlet155with the volume of the compensating member92that is withdrawn during closing of the nozzle133, any dripping of residual liquid in the nozzle outlet155when the nozzle133is closed is avoided. Similarly, by balancing the gain in volume at the nozzle outlet155with the loss of volume when the compensating piston92drops into the passageway95when the nozzle133is opened, fresh liquid fills the nozzle outlet155and presents a liquid surface that is flush with the nozzle outlet155. Seal members96,97may be disposed between the nozzle body161and the slider cover91and seal members98,99may be disposed between the slider162and the nozzle body161as shown inFIG. 25.

FIG. 26illustrates another nozzle233that also includes a nozzle body261and a slider cover291. A compensating piston292may be coupled directly to the slider cover291and, in the embodiment illustrated inFIG. 26, is partially disposed in the inlet234to the nozzle body261. When the slider261and nozzle body291are shifted to the left inFIG. 26to arrive at a closed position with the gate269engaging the distal wall273, the compensating member292is partially withdrawn from the inlet234or nozzle body261thereby creating available volume, or a slight vacuum or suction which will draw liquid upward from the nozzle outlet255and into the through passageway295. Conversely, when the nozzle233is opened, the increased volume at the nozzle outlet255is balanced by the decrease in volume caused by the compensating member292reentering the inlet234or passageway295. By balancing the increase in volume at the nozzle outlet255with the decrease in volume caused by the compensating member292reentering the inlet234or passageway295, the nozzle outlet255becomes charged with fresh liquid with a surface that is flush with the nozzle outlet255. Like the nozzle133shown inFIG. 25, the actuator pin235couples the slider cover291to the slider262and seal members296,297may be disposed between the nozzle body261and the slider cover291and seal members298,299may be disposed between the slider262and the nozzle body261.

FIG. 27illustrates yet another nozzle333without a slider cover91or291. The nozzle body361includes an inlet334and an outlet363that couples to an outlet body354. The outlet body354includes a distal wall373for sealingly engaging the gate369of the slider362. The slider362includes a compensating member392. The compensating member392partially extends out of the outlet body371as the slider362moves to the closed position. By pushing a portion of the compensating piston392out of the through passageway395when the nozzle333is closed, available volume in the passageway295is created that draws any residual liquid upward from the nozzle outlet355and into the through passageway395without dripping. Conversely, when the nozzle333is opened, the gate369moves away from the wall373, thereby creating available volume for liquid that is balanced by the compensating member392reentering the passageway395. As a result, liquid enters the nozzle outlet355as the nozzle333is opened, charging the nozzle outlet355with liquid that presents a surface that is flush with the nozzle outlet355. Again, an actuator pin335couples to the slider362.

The nozzles33,33b,133,233,333include generally rectangular nozzle outlets55,55b,155,255,355. The creation and maintenance of a “flush” liquid supply at a nozzle outlet455as a gate469moves towards or away from a closed position is illustrated schematically inFIGS. 28-30. As discussed above, referring toFIGS. 28-29, when the gate469moves towards the wall473to close the nozzle433, liquid disposed in the outlet455begins to be drawn away from the outlet455and into the nozzle433, without dripping and while maintaining a supply of liquid at the nozzle outlet455that presents a flush surface500with the nozzle outlet. Conversely, as the gate469moves away from the wall473towards a fully open position, liquid reenters the nozzle outlet455and the flush surface500of the liquid at the nozzle outlet455is maintained.

However, this disclosure is not limited to rectangular or 4-walled nozzle outlets. For example,FIGS. 30-33illustrate a nozzle533with a nozzle outlet555that is of the iris-type. As the nozzle outlet555is closed (FIG. 32), the compensating member592is withdrawn from the outlet body554. This action draws liquid up into the outlet body554without dripping. Similarly, as the nozzle outlet555is opened, the compensating member592reenters the outlet body554causing liquid to charge the nozzle outlet555as it is opened and as discussed above the other embodiments.FIG. 33shows an alternative to a compensating member in the form of a bellows592a. Various alternatives to a compensating member592other than a bellows592awill be apparent to those skilled in the art.

INDUSTRIAL APPLICABILITY

An actuation system for a liquid dispenser30is shown and described. The liquid dispenser30includes a stationary and circular array of nozzles31that may be individually actuated by upwardly protruding actuator pins35. The actuator pins35may be actuated one at a time. Two stationary motors39,41are used to rotate an actuator implement48aaround the circular array of nozzles31until a selected nozzle33is arrived at. Then, the actuator motor41is activated again which results in rotation of the actuator implement48awhich engages the actuator pin35of the selected nozzle33thereby partially or fully opening the nozzle33or fully closing the nozzle33.

The two motors39,41of the actuation system may be mounted on a stationary table or platform38. Because the circular array of nozzles31is stationary, all motors used to drive the liquid dispenser30remain stationary, resulting in a simplified design with less moving parts and less problems associated with motors mounted on moving parts or platforms.

Improved nozzles33,133,233,333,433,533are also disclosed inFIGS. 5A-7A, 5B-7B and 25-27respectively, which include sliders62,62b,162,262,362that include gates69,69b,169,269,369,469that move from a fully closed position through multiple open positions as well as a fully open position while maintaining a supply of liquid at the nozzle outlets55,55b,155,255,355,455,555that remains flush with the outlets55,55b,155,255,355,455,555and that does not drip. The extent to which the gates69,69b,169,269,369are opened can be controlled by the disclosed actuator system20and therefore the output flow may controlled. The disclosed nozzles33,33b,133,233,333are designed with a sniff back function that prevents dripping when the nozzles33,33b,133,233,333,433,533are being closed and a reverse sniff back function that maintains a liquid surface500at the nozzle outlets55,55b,155,255,355,455,555. The disclosed nozzles33,33b,133,233,333,433,533are not prone to plugging or clogging.