ES2355243T3 - A DISPENSER THAT HAS A ROTATING ACTUATOR ASSEMBLY. - Google Patents

Abstract

A dispenser, comprising: an actuator section (104) having a first movable member (108); a hydraulic section (102) coupled to said actuator section (104) and having a second movable member (110), adapted said hydraulic section (102) to dispense a liquid from an outlet (122) and adapted said actuator section (104) to control the dispensing of the liquid; a rotating lever arm (230) having a first end (236) operatively coupled to said first movable member (108) in said actuator section, and further including a second end (238) operatively coupled to said second mobile member (110) in said hydraulic section (102), wherein said first mobile member (108) is operative to move said second mobile member (110) between open and closed positions to start and stop respectively the flow of liquid from said outlet (122), characterized in that a flexible non-diaphragm seal (232) is positioned between said hydraulic section (102) and said actuator section (104) and adapted to prevent liquid from seeping into said actuator section (104); and because said rotating lever arm (230) extends from said first end (236) through said seal (232) and towards said hydraulic section (102).

Description

A dispenser that has a rotation actuator assembly.

Field of the Invention

This invention generally relates to liquid dispensing devices used for a variety of purposes, but particularly useful for viscous liquids such as hot melt adhesives, sealing compounds, paints, etc. Such devices are called fluid control valves or guns or dispensing modules.

Background of the invention

A typical dispensing device for supplying liquid, as a hot melt adhesive, generally includes a body having a valve stem that opens and closes a dispensing orifice. The valve stem is normally operated in at least one direction by pressurized air to dispense differentiated amounts of pressurized liquid 10. A spring mechanism or pressurized air is used to move the valve stem in an opposite direction against a valve seat. This stops the flow of liquid from the dispensing hole.

More specifically, the devices generally related to the present invention include a liquid passage adjacent to the dispensing orifice and an actuator cavity or chamber at an opposite end of the device. The actuator cavity contains a portion of the valve stem that connects with a 15-piston member and also connects with a spring return mechanism, as discussed above. Under sufficient air pressure applied on one side of the piston member, the valve stem moves in a direction opposite to the valve seat to discharge liquid. When the air pressure is relieved, the spring mechanism will automatically return the valve stem to a normally closed position against the valve seat. Such spring mechanisms generally include an adjustment to vary the compression of the spring and therefore vary the amount of air pressure required to open the valve. The spring compression adjustment will also adjust the bias force used to close the valve. These devices also include a stroke adjustment, or the spring compression adjustment also varies the stroke of the valve stem to adjust the flow rate.

Despite the broad success of the devices as described above, an improvement is desired. For example, a dynamic seal generally placed between the dispensing body and the valve stem in motion usually prevents the liquid from seeping into the actuator cavity. It is conventionally understood that dynamic seals are seals between two surfaces that move relative to each other. These dynamic seals can press tightly against the valve stem and cause friction and seal wear. Higher friction may place greater demands on the requirements for pressurized air to move the valve stem. On the other hand, the selection of a looser dynamic seal could result in improper sealing, thereby allowing the liquid to lock the piston and pressurized air into the liquid passage, causing unwanted dispensing discontinuities. Even with reduced friction, the dynamic seal will wear out over time and lose its ability to seal properly. A dispenser according to the preamble of claim 1 is known from US-2002/0002943-A. 35

It would therefore be desirable to provide a dispenser that eliminates or reduces the need for dynamic seals in contact with the pressurized liquid, thereby eliminating or thereby reducing problems such as those mentioned above.

This object is solved by the dispenser of claim 1.

Summary of the Invention 40

Thus, certain embodiments of the present invention relate to a dispenser that includes an actuator section having a first movable member and a hydraulic section coupled to the actuator section in a juxtaposed configuration and having a second movable member. The hydraulic section includes an outlet and is adapted to dispense liquid from it and the actuator section is adapted to control the dispensing of the liquid. The dispenser further includes an actuator assembly that operatively couples the first mobile member 45 to the second mobile member, in which the first mobile member is operative to move the second mobile member between the open and closed positions to start and stop respectively the liquid flow from the outlet.

The actuator section may be a pneumatic section in which the first movable member is configured as a piston that is adapted to move in response to the pressurized fluid. The dispenser may also include a solenoid to deliver pressurized fluid to the piston. A polarization member, such as a spring, can be coupled to the piston to polarize the piston in a preferred direction. In the exemplary embodiment, the hydraulic section has a second movable member configured as a needle capable of alternating movement within the hydraulic section. The hydraulic section includes an intake to couple the hydraulic section to a source of pressurized liquid and an outlet through which the liquid is dispensed. The hydraulic section may also include a polarization element, such as a spring, that polarizes the needle in a preferred direction. 55

The actuator assembly includes a rotating lever arm that has a first end coupled to the piston and

a second end coupled to the needle. In one aspect of the invention, the second end of the rotating lever arm is coupled to the needle at a point located between the intake and the outlet. The coupling of the end of the rotating lever arm to the second movable member, such as the needle, between the intake and the outlet advantageously reduces or eliminates the stagnation points and consequently reduces or eliminates the formation of carbonaceous residues and other material accumulation within the hydraulic section. The actuator assembly also includes a flexible seal 5 coupled to the rotating lever arm and adapted to position between the actuator section and the hydraulic section to prevent liquid from leaking into the actuator section. The seal is a non-diaphragm seal in which the periphery of the seal is not restricted and is able to flex to accommodate the movement of the rotating lever arm while retaining a fluid tight seal. The seal may also be adapted to withstand high hydraulic working pressures, such as from approximately 551,580.56 Pa to at least 10,342,135.5 Pa and 10 other pressure ranges. A bushing support that attaches to the swivel lever arm and holds the seal can be provided. The bushing support is positioned radially into the periphery of the seal. Also, the actuator assembly can also include a turning member, such as a turning pin, coupled to the rotating lever arm and adapted to define a fixed turning point around which the rotating lever arm rotates.

It is contemplated that the variations of the dispenser described above are within the scope of the present invention as long as they fall within the scope of the claims. For example, in some embodiments of the invention, the actuator section is an electrical section in which the first movable member is configured as an armature that is adapted to move in response to an electric current. The first end of the rotating lever arm is then coupled to the armature such that the movement of the armature moves the second movable member, like a needle, between the open and closed positions. In other embodiments of the invention, the second movable member within the hydraulic section is configured as one or more shoes. The shoes are adapted to alternate the movement within the hydraulic section between the open and closed positions to start and stop respectively the flow of liquid from the outlet. Further embodiments of the invention include a hydraulic section configured to operate in a re-aspiration mode, a three-way mode or both. 25

These and other objects, advantages and features of the invention will become more readily apparent to those with basic knowledge in the field by reviewing the following detailed description taken in conjunction with the accompanying drawings.

Brief description of the drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate 30 embodiments of the invention and, together with a general description of the invention given above, and the detailed description given below, serve to explain the invention.

FIG. 1 illustrates a schematic perspective view of a dispenser in which a hydraulic section and an actuator section are arranged juxtaposed according to the invention;

FIG. 1A illustrates a partial sectional view of the dispenser of FIG. 1 taken generally along line 1A-1A;

FIG. 2 illustrates a sectional view of an exemplary dispenser having an actuator assembly according to the invention;

FIG. 3 illustrates a partial sectional view of an exemplary actuator assembly according to the invention;

FIG. 3A illustrates a sectional view of the exemplary actuator assembly of FIG. 3; 40

FIG. 4 illustrates a sectional view of an exemplary dispenser according to the invention in which the actuator assembly is operatively coupled to a liquid dispensing passage;

FIG. 5 illustrates a sectional view of an exemplary dispenser according to the invention that includes a recirculation port;

FIG. 6 illustrates a sectional view of an exemplary dispenser according to the invention that includes a re-aspiration operation;

FIG. 7 illustrates a sectional view of an exemplary dispenser according to the invention that includes a self-aligning needle;

FIG. 8 illustrates a sectional view of an exemplary dispenser according to the invention that includes a re-aspiration operation and a recirculation port; fifty

FIG. 9 illustrates a sectional view of an exemplary dispenser according to the invention using a shoe in the hydraulic section according to the invention;

FIGS. 10 and 11 illustrate alternative rotating lever arms according to the invention useful with the exemplary dispenser of FIG. 9;

FIG. 12 illustrates a perspective view of a dispenser according to the invention in which the solenoid and the actuator section are formed as an integral assembly;

FIG. 12A illustrates a sectional view of the dispenser of FIG. 12 usually taken along line 12A-12A;

FIG. 13 illustrates a sectional view of an exemplary dispenser according to the invention that includes a pressure balanced hydraulic section; Y

FIG. 14 illustrates a sectional view of an exemplary dispenser according to the invention in which the actuator section is configured as an electrical section.

Detailed description

FIG. 1 is a schematic representation of an exemplary dispenser according to the invention. Unlike the previous dispensers, the dispenser of the invention includes a hydraulic section 102 and an actuator section 104 arranged juxtaposed rather than in a vertical manner. Since the hydraulic section 102 is often coupled to a heated manifold or other heater block, the present juxtaposed arrangement allows the actuator section 104 to be thermally insulated from such heater block. As a result, the o-rings and other seals within the actuator section 104 should not be exposed to the same elevated temperatures as has been experienced in conventional dispensers. Additionally, other electrical components, such as solenoids, will not be exposed to high temperatures either. This allows the closest coupling of the solenoid to the actuator section, which improves the response time. Taken together, the juxtaposed arrangement will provide increased reliability and performance compared to conventional vertically arranged dispensers. twenty

As shown in FIG. 1A, an exemplary dispenser according to the invention generally includes a hydraulic section 102, an actuator section 104, and an actuator assembly 106. The hydraulic section 102 receives a pressurized liquid, for example, liquid hot melt adhesive, from an intake 103 and dispenses the liquid through an outlet, such as the nozzle 107. The actuator section 104 includes a first mobile member 108 and the hydraulic section includes a second mobile member 110. Actuator assembly 106 operatively couples the first mobile member 108 to the second mobile member 110 such that the first mobile member 108 is operable to move the second mobile member 110 between the open and closed positions to start and stop respectively the dispensing of the liquid. The first mobile member 108 is coupled to an actuator 112 that is capable of moving the first mobile member 108. A polarization force 114 can be applied to a first mobile member 108 to polarize the first mobile member in a preferred direction. The actuator section is adapted to control the dispensing 30 of liquid by the hydraulic section 102 by controlling the movement of the first movable member 108.

The hydraulic section 102 and the actuator section 104 can be coupled to each other by a variety of procedures. For example, in FIG. 1, four bolts 116 are used to connect the actuator section 104 and the hydraulic section 102 to each other. Also, the hydraulic section 102 includes a face 118 that is coupled to a dispensing manifold (not shown) of a liquid dispensing system. For example, through bolt holes 35 can be used 120 to couple the hydraulic section 102 to the manifold (not shown). When coupled, the hole 122 cooperates with an outlet port of the manifold so that pressurized liquid (e.g. 3,447,378.5 Pa) is received within the hydraulic section 102. As explained in more detail below, this Pressurized liquid is dispensed from the nozzle 107 precisely and accurately. In advantageous embodiments, the hydraulic section 102 is constructed of a material that can be transferred by heat, including non-interactive metals such as aluminum, brass, or stainless steel while the actuator section 104 may be constructed of a metal or a temperature resistant plastic, including fluorinated plastic.

The following figures and the description thereof provide various embodiments of the invention showing different configurations of the hydraulic section 102, the actuator section 104 and the actuator assembly 106. For example, as described below, the actuator section 104 may be configured as a pneumatic section, in which a pressurized fluid controls the movement of a piston or an electrical section, in which the electric current controls the movement of an armature. Additionally, the hydraulic section 102 may have many different configurations, such as including a needle, a ball or one or more shoes capable of alternating movement within the hydraulic section that cooperates with a valve seat to start and stop the dispensing of liquid by the nozzle 107. The hydraulic section 102 may also be configured with a re-suction feature, a three-way feature or both. Thus, although various embodiments of the invention are shown and described herein, the invention is not as limited as those with basic knowledge in the art will recognize other configurations that can be used with the invention.

FIG. 2 represents a sectional view of an exemplary dispenser according to an embodiment of the invention. Solenoid 206 and manifold 217 are shown as simple blocks since their operation is well understood by someone with basic knowledge in this field. In particular, solenoid 206 acts so that 45 distributes pressurized air 208 in a controlled manner to a piston 212 of the pneumatic section 204. The manifold 217 acts so that it distributes pressurized liquid 216 to the hydraulic section 202. This sectional view does not represents the

Bolts or other connectors that can be used to secure hydraulic section 202 to pneumatic section 204. Nor does it represent valve guides or stroke adjustment mechanisms that are often included within the hydraulic section of a dispenser.

The hydraulic section 202 includes a chamber 218 that receives the pressurized liquid 216. Inside the chamber 218 there is a needle 220 that is configured to fit into a valve seat 221. When the needle 220 fits into the valve seat 221 , no pressurized liquid travels from the chamber 218 through the passage 223 and out of the hole 224 of the nozzle 222. However, when the needle 220 is positioned so that it does not fit into the valve seat 221, then the Pressurized liquid exits the chamber 218 through the passage 223. Thus, by controlling the position of the needle 220, the dispensing of pressurized liquid from the hole 224 can be controlled accurately and precisely. In addition to a needle valve as shown in FIG. 2, a ball and a seat can also be used to control the dispensing of pressurized liquid.

Someone with basic knowledge will recognize that a series of alternative hydraulic sections is contemplated in addition to the specific exemplary hydraulic section 202 of FIG. 2. For example, alternative hydraulic sections contemplated within the scope of the present invention may include heating blocks or integrally formed heating elements. Additionally, exemplary hydraulic sections can be formed integrally with a manifold, or other similar assembly. In addition, the term "needle" is used in a generic sense and is intended to encompass a wide range of moving members that have a variety of shapes and contours.

The pneumatic section 204 includes a piston 212 that is polarized upwardly through a spring 214. In operation, the pressurized air 208 is distributed to the piston 212 with sufficient force to overcome the spring 214 and move the piston 212 down. twenty

The piston 212 of the pneumatic section 204 and the needle 220 of the hydraulic section 202 are operatively coupled to each other through a rotating lever arm 230. The arm 230 includes an end 236 that is coupled to the piston shaft 213. For example, the end 236 may be ball-shaped and fit into a through hole 237 machined in the shaft 213. As an alternative to the through hole 237, a blind hole can be machined in the shaft to receive the end 236 in a manner wherein the end 236 is free to rotate within the blind hole. Similarly, the other end 238 of the arm 230 can be coupled to the needle 220. The arm 230 rotates around a pivot point 234 so that the downward movement of the piston 212 results in an upward movement of the needle 220. On the contrary, the upward movement of the piston 212 results in a downward movement of the needle 220. The pivot point 234 can be achieved by a variety of functionally equivalent procedures but may include, for example, a pin that it passes through the center of the arm 230. The end of the pin can be held in a recess or cavity formed in the hydraulic section 202 such that the pin is free to rotate and therefore allows the arm 230 to rotate.

Seal 232 is located between hydraulic section 202 and pneumatic section 204 to prevent pressurized liquid 216 from leaking into pneumatic section 204. Unlike previous dispensers, seal 232 is not a dynamic seal around an alternative shaft. . Instead, the seal 232 is a flexible seal around the swivel lever arm 230 that can flex or "swing" when the swivel lever arm 230 is moved. Thus, the flexible seal 232 acts better and lasts longer than previous dynamic stamps. Additionally, seal 232 is not a diaphragm seal that is supported along its outer periphery and prevented from moving along its outer periphery. Instead, the seal 232 is preferably substantially annular with its inner edge surrounding the arm 230 and its unrestricted outer edge although sealingly fitted on the outside of the hydraulic section 40 202. In this way, the seal 232 can be flexed to along its periphery so as to accommodate the rotational movement of the rotary lever arm 230. Also, as explained in more detail below, the seal 232 is held from inside the seal 232 instead of being held along the periphery, as is typical of diaphragm seals. In addition to an annular shape, alternative shapes can be used for the seal 232, such as square or rectangular. As depicted in FIG. 2, the hydraulic section 202 is shaped so that a cavity is created for the seal 232 in which to sit. As those with basic knowledge in the art will recognize, however, a cavity may alternatively be formed in the actuator section 204. The seal 232 is preferably made of an elastic or flexible material such as, for example, an elastomeric material that is deformable. so that when the pneumatic section 204 and the hydraulic section 202 are coupled together, the seal 232 is slightly compressed in the area of the cavity and provides a seal between the two sections 202 and 204. 50

Although not explicitly represented in FIG. 2, chamber 218 may include an adjustment mechanism for needle 220 as is known in the art. A needle stroke adjustment mechanism usually includes a physical stop within the chamber 218 that limits the amount of displacement of the needle 220. The embodiments of the present invention are capable of operating with the wide variety of mechanisms of Needle stroke adjustment that are known in this field. 55

FIGS. 3 and 3A represent an exemplary actuator assembly comprising a flexible seal portion 304 and a sleeve holder 312, such as a washer, formed around a rotating lever arm 306. As described above, seal 304 sits within an appropriately shaped cavity formed by the joining surfaces of an actuator section and a hydraulic section of a liquid dispenser.

A turning pin 302 extends through the swivel lever arm 306 and can be attached thereto, such as 60

by a press fit, and also extends through the flexible seal 304 such that the rotating lever arm 306 rotates around a pivot point defined by the pin 302. The material from which the flexible seal 304 is constructed can be any of a variety of elastomers or plastics available, such as, for example, the fluorinated elastomer marketed as Viton®. The bushing support 312 radially holds the seal 304 from the center, unlike a diaphragm seal that is supported along its periphery. The bushing support 312 also 5 provides support for the flexible seal 304 to withstand the hydraulic pressure that generally operates along the main axis of the rotating lever arm 306. In this way, the seal 304 can be configured to withstand relatively low hydraulic pressures. large, such as from approximately 551,580.56 Pa to at least 10,342,135.5 Pa. Seal 304 may also be configured for other hydraulic pressure ranges. For example, seal 304 may be configured to withstand a hydraulic pressure from approximately 689,475.7 Pa to approximately 10,342,135.5 Pa 10. Preferably, seal 304 may be configured to withstand hydraulic pressures from approximately 1,378,951.4 Pa to approximately 10,342,135.5 Pa. More preferably, seal 304 may be configured to withstand a hydraulic pressure from approximately 2,068,427.1 Pa to approximately 6,205,281.3 Pa. Even more preferably, seal 304 may be configured to withstand hydraulic pressures from approximately 2,757,902.8 Pa to approximately 5,515,805.6 Pa. fifteen

Thus, in an advantageous embodiment, the bushing support 312 is made of a rigid material such as brass, or other metal, and coupled to the rotating lever arm 306 and the flexible seal 304. The bushing support 312 may include a semicircular cavity 320 adapted to receive pin 302 therein. The bushing support 312 may not rigidly engage the pin 302 so that the bushing support 312 and the pin 302 can move relative to each other. The flexible seal 304 may be molded above the rotating lever arm 20 306. In addition, the rotating lever arm 306 may advantageously include a profile that provides more surface area in the rotating lever arm 306 so that the flexible portion 304 grab. This profile, for example, may include ridges 314 or grooves. Alternatively, or in addition, the flexible seal 304 can be attached to the rotating lever arm 306. In the exemplary embodiment of FIG. 3, flexible seal 304 includes a low relief portion 305. However, this shape is exemplary in nature and other shapes are also contemplated.

As shown in FIG. 3A, the bushing support 312 includes a hydraulic face 322 and an actuating face 324. The hydraulic face 322 borders seal 304 and is in a plane that passes through a pivot point defined by the crossing of pin 302 and the arm of rotating lever 306. The bushing support 312 also includes a bore 326 adapted to receive the rotating lever arm 306 therethrough. The bore 326 has a hydraulic end 328 that has a diameter substantially equal to the diameter of the swivel lever arm 306. In this way, the hydraulic face 322 can fully withstand seal 304 and further prevent extrusion of seal 304 in bore 326 The bore 326 is further configured to increase in diameter in a direction towards the actuating end 330. For example, the bore 326 may generally be cone-shaped. Increasing the diameter of the bore 326 from the hydraulic end 328 to the actuating end 330 provides a clearance 332 allowing the rotating lever arm 306 to rotate, as illustrated by the translucent lines in FIG. 3A.

The swivel lever arm 306 includes an end 308 that engages the second movable member in the hydraulic section, such as the needle 220 in FIG. 2, and another end 310 that engages the first movable member in the actuator section, such as piston 212 in FIG. 2. When coupled in this manner, the rotating lever arm 306 rotates around a point where the arm 306 is crossed by the pin 302 and, thus, the upward or downward movement of the end 310 results in a 308 end movement directed in the opposite direction. The swivel lever arm 306 and pin 302 are advantageously made of high strength steel. However, other materials such as brass, aluminum or a high strength or composite non-metallic material can also be used.

When the rotary lever arm 306 is moved, the flexible seal 304 flexes but maintains a seal along its outer periphery and also between itself and the rotary lever arm 306. Such a small amount of flexion will not alter the arrangement of seal provided by seal 304. The construction of flexible seal 304 of 40 Viton® or similar material will allow angular deflection of approximately 4.5 degrees without compromising the seal between a hydraulic section and an actuator section. Thus, although flexible portion 304 can be flexed when rotating arm 306 is moved, it still acts as a flexible seal that will last longer and be more reliable than previous dynamic seals for alternative shafts. Different materials and seals of different sizes can be used if an angular offset greater than about 4 to 5 degrees is desired. Four. Five

Additionally, in a vertical arrangement of the prior art of the hydraulic and actuator sections, there is a substantial hydraulic pressure that pushes the second movable member back out of the hydraulic section towards the actuator section. The hydraulic pressure of the pressurized liquid within the hydraulic section acted to push the second movable member in a direction opposite to the force supplied by the actuator section. Thus, it was required that the actuator section be sized to overcome this additional hydraulic force. In the present embodiments that have a juxtaposed arrangement, such as that shown in FIG. 2, the pressurized liquid 216 within the hydraulic section 202 still exerts a force against the rotating lever arm 230 but this force is transverse to the direction of movement of the piston 212. This transversely directed force is transferred to the support surfaces of the support 312, not to piston 212. In the embodiment of FIG. 3 for example, the force is transferred by the rotation pin 302, although means 55 are contemplated

Alternate load support. The bushing support 312 transfers the load to the pneumatic body 204 while the ball end 308 of the rotating lever arm 306 is designed to fit in the opening 237 (see FIG. 2) with clearance so that no load is transferred transverse to piston 212.

FIG. 4 illustrates an alternative embodiment of a dispenser in which the hydraulic section does not include a needle. The dispenser of FIG. 4, includes a hydraulic portion 402, a pneumatic portion 404, and a solenoid portion 403. As described above, the solenoid portion 403 distributes a pressurized air 406 in a controlled manner to the piston 412. In response, the piston 412 is moved down by pressurized air 406 or driven up by a spring 416.

According to this embodiment, a rotating lever arm 414 extends from the pneumatic section 404, through a seal 418, into a chamber 410 of the hydraulic section 402. The rotating lever arm 414 fits 10 into the spring 416 in a end 413 and a passage 422 at the other end 415. The spring 416 operates to push the swivel lever arm 414 up against the piston 412. In response to pressurized air 406 sufficient to overcome the spring 416, the piston 412 operates to push down on the swivel lever arm 414. The up and down movement of the swivel lever arm 414 makes it rotate about a pivot point 419, like a pin. The rotation of the rotating lever arm 414 causes the opposite end 415 to move in a direction (up or down) opposite that of the end 413.

The hydraulic section 402 includes an intake 408 for receiving pressurized liquid, such as, for example, hot melt liquid adhesive. This liquid is received in a chamber 410 and exits through a passage 422 out of a hole 424. At the end 415 of the rotary lever arm 414 inside the chamber 410, there is a attached shoe 420 that fits above the passage 422. When the end 415 is lowered, the shoe 420 covers an opening to the passage 422 20 so that the passage 422 is blocked and no liquid is dispensed from the hole 424. However, when the end 415 is raised so that the passage 422 is no longer blocked by the shoe 420, then the liquid leaves the chamber 410 through the hole 424. The shoe 420 can be adhered to the arm 414 in a variety of ways and can be constructed of a material that can advantageously seal passage 422 such as plastic, elastomer, rubber or a high performance fluorocarbon material. Additionally, instead of a flat rectangular shape, the shoe 420 may have alternative shapes, such as a ball.

When the arm 414 is positioned so that the liquid is being dispensed from the hole 424, the portion of the arm 414 inside the chamber 410 is hydraulically balanced. Although the liquid inside the chamber 410 is under pressure, the pressure in the upper part and the lower part of the arm 414 is compensated. A hydraulically balanced arm allows faster movement of the end 415 and its closing action with the passage 422. 30 Additionally, the force necessary to move the arm 414 is also reduced. For example, pressurized air 406 at between 137,895.14-275,790.28 Pa and in quantities of 0.1 cc to 0.5 cc is sufficient to operate piston 412. As a result, a smaller piston can be used that gives as a result a smaller dispensing module. In previously described embodiments (and embodiments described below), the end 415 of the rotating lever arm 414 is sometimes replaced by a needle. In these embodiments, too, the juxtaposed arrangement of the hydraulic section and the pneumatic section create a hydraulically balanced needle such that when the valve is open, the hydraulic forces on the needle cancel each other out and the needle "floats" "in liquid. As a result, the resistance to close the needle is reduced, or eliminated, making it easier for the needle to close.

Another embodiment of the invention is illustrated in FIG. 5. Similar to previous drawings, the general components of the dispenser are the same. A manifold 505 is coupled to a hydraulic section 502 that is coupled, juxtaposed, to a pneumatic section 504. A flexible seal 520 is located between the two sections and prevents the liquid from the hydraulic section 502 from leaking into the pneumatic section 504. A rotating lever arm 518 operatively couples a piston 512 of the pneumatic section 504 to a needle 510 of the hydraulic section 502. A solenoid section 503 delivers pressurized air 514 in a controlled manner to the piston 512 so that it can push down 45 against the spring 516 in order to control the movement of the needle 510.

The dispenser of FIG. 5 differs from previous dispensers in that it includes an intake port 508 for receiving a pressurized liquid, such as hot melt liquid adhesive, as well as a recirculating port 506 for diverting the pressurized liquid back to the manifold section 505. Such a dispenser is called commonly three way dispenser. As depicted in FIG. 5, the end 522 of the needle 510 sits 50 inside a seat 523 in order to prevent the liquid from leaving the chamber 530 through the dispensing hole 526. Instead, the liquid inside the chamber 530 moves up to the recirculation port 506 where it returns to the manifold section 505. If the needle 510 moves up, as if moving the piston 512 down, then the end 524 of the needle 510 will block the seat 525 of the port recirculation 506. In this configuration, the end 522 will no longer fit tightly in the seat 523 and the liquid from the chamber 530 will be dispensed through the hole 526.

An alternative embodiment, to those already described, is represented in FIG. 6. According to this embodiment, a hydraulic section 602 is coupled to a pneumatic section 604 in a juxtaposed manner. Between the two sections a cavity is formed on their joining faces to securely maintain a flexible seal 616 having a rotating lever arm 612 extending therethrough. The rotary lever arm 612 operatively connects the piston 608 of the pneumatic section 604 with the needle 618 of the hydraulic section 602 such that the

Piston movement 608 results in a movement of the needle 618.

In contrast to the previously described embodiments, piston 608 of FIG. 6, moves up in response to solenoid 603 which provides pressurized air 606 while spring 610 pushes piston 608 down when no pressurized air 606 is being applied. Upward movement of piston 608 causes needle 618 to descend so that the end 624 no longer fits into the valve seat 626. With the needle 618 in this position, the liquid inside the chamber 619 (received through an intake port 620) is dispensed out to through the hole 622. When the piston 608 moves down, the needle 618 moves up and causes the end 624 to fit into the valve seat 626 thereby interrupting the dispensing of any liquid within the chamber 619. This type of movement of the needle 618 is known as "re-aspiration" and provides the benefit that the needle 618 tends to attract liquid upward from the hole 622 when the end 10 624 is engaged. ja in seat 626 instead of forcing the liquid out of the hole 622.

FIG. 7 represents another three-way liquid dispenser that has a recirculation flow for the liquid. The liquid enters the chamber 711 of the hydraulic section 702 through an intake port 710 and can exit the dispensing hole 712 or a recirculating port 708. Depending on the position of the needle 715, the end 718 will fit sealed in the seat 719 or the other end 716 will fit tightly 15 in the seat 717. The position of the needle 715 is controlled by the swivel lever arm 714 extending from the hydraulic section 702 to the section pneumatic 704. The rotating lever arm 714 passes through a flexible seal 720 and rotates around a pivot point 721, as defined by a pin. One end 722 of the arm 714 fits into the piston 724 and the other end 723 fits into the needle 715. The spring 726 acts to force the piston 724 down and the solenoid section 703 delivers pressurized air 728 to drive the piston 724 upwards. twenty

In particular, the end 723 can be spherical in nature and interact with a through hole 730 drilled in the needle 715 without being rigidly fixed to each other. When the end 723 moves up and down, a tangential point on its spherical surface comes into contact with the inner surface of the through hole 730. Additionally, the seats 717 and 719 are shaped to complement the ends 716 and 718 of the needle. 715. Thus, when one end 716, 718 moves towards a seat 717, 719, respectively, the needle 715 is driven to align with the seat 717, 719 since the needle 715 is free to wobble around its connection with the end 723 of the swivel lever arm 714. Thus, the needle 715 is self-aligning.

In contrast, the standard vertical arrangements of the pneumatic and hydraulic sections in dispensing guns create a situation in which the needle in the pneumatic section is not self-aligning. The rigid connection 30 of the needle to the actuator piston as well as the dynamic seal below the piston restrict the movement of the needle so that it does not automatically align itself with the valve seat while it is moving to the closed position.

FIG. 8 illustrates an embodiment of the present invention that incorporates both a three-way dispenser and a re-aspiration operation. The hydraulic section 802 includes a needle 806 that is closed at the dispensing end 35 810 through an upward movement, thereby providing the re-aspiration operation. Additionally, the end 808 is interconnected with a recirculation port 809 in order to provide a liquid return path to the manifold 805. The pneumatic section 804 and the solenoid section 803 operate as described above to cause the piston 811 to move the swivel lever arm 812 in a manner in which the movement of the needle 806 is controlled. 40

FIGS. 9 and 10 illustrate two different embodiments of the invention that provide a three-way implementation without the presence of a needle within the hydraulic section. In particular, the hydraulic section 902 includes a recirculation port 934 and an intake port 932. Pressurized liquid, as a hot melt liquid adhesive is received from a manifold (not shown) through the intake port 932 and can return to the manifold a through the recirculation port 934. These ports 932, 934 may include a respective O-ring 45 918, 916 or similar device to provide a liquid seal when the hydraulic section is coupled to the manifold (not shown).

A solenoid 903 provides pressurized air 905, or other fluid, to operate the piston 906 of the pneumatic section 904. In particular, the pressurized air 905 operates to push the piston 906 down against the force of the spring 908 that drives the piston 906 towards above. A rotating lever arm 910 extends from within the pneumatic section 904 to the hydraulic section 902. This rotating lever arm 910 rotates around a pivot point 914, such as a pin. The rotating arm 910 also passes through a flexible seal 912, preventing the seal 912 from having the pressurized liquid inside the hydraulic section 902 seep into the pneumatic section 904.

One end 909 of the rotating lever arm 910 fits into the piston 906 so that the movement of the piston 906 results in the movement of the end 909. When the end 909 moves, it causes the rotating lever arm 55 to rotate or rotate thus causing the end 911 to move. The end 911 of the rotary lever arm 910 is located within the hydraulic section 902 and moves in the opposite direction to the other end 909. Also, this end 911 includes two shoes 922, 924 that adhere to it. When the end 911 moves up, the shoe 922 fits into the seat 928 and closes the recirculation port 934. Simultaneously, the shoe 924 is disengaged from the seat 926 thereby allowing the liquid to enter the passage 60

930 and be dispensed through the hole 920. When the end 911 moves down, the shoe 924 and the seat 926 close the passage 930 and the shoe 922 and the seat 928 are disengaged so that the liquid is allowed to flow through of the recirculation port 934. These shoes are similar in construction to the shoe 420 described in relation to FIG. Four.

The embodiment of FIG. 10 is substantially similar to that of FIG. 9 except for the end of the 5 swivel lever arm within the hydraulic section. In particular, the swivel lever arm 1010 includes an end 1009 that fits into the piston 906 as before. However, end 1011 does not include the use of additional shoes. Instead, the end 1011 is shaped to effectively engage the seats 926 and 928. Thus, the end 1011 of the swivel arm 1010 opens and closes the liquid passages to the recirculating port 934 and to the dispensing hole 920 10

FIG. 11 illustrates an alternative embodiment for the swivel lever arm 1010 of FIG. 10. In this particular embodiment, the flexible seal 1102 is formed as before but has a portion 1104 that substantially encloses the end 1011 of the rotating lever arm 1010. The portion 1104 provides an elastic surface that advantageously cooperates with the valve seats 926 and 928 to provide fluid tight seals and additionally block the movement of any liquid between seal 1102 and swivel lever arm 1010.

FIGS. 12 and 12A show an alternate embodiment of a dispenser having a pneumatic section with a double acting piston coupled to a solenoid to supply pressurized fluid, such as air, to both sides of the piston. The alternative embodiment of FIG. 12 includes a solenoid 1202 and a housing 1203. The solenoid 1202 includes a coil 1204 and an armature composed of the body 1209 and the shaft 1208. By the electric current supplied to the coil 1204, through an electrical connector 1206, creates an electric field that moves the armature (1208, 1209) up and down. The housing 1203 includes a series of passages and a reel or head 1217. The head 1217 is pushed down by the armature shaft 1208 and a spring 1219 drives the head 1217 up against the force of the tree 1208. Included within the housing 1203 there is a first exhaust port 1210, a second exhaust port 1214 and an air intake port 1212. 25 There is also a first passage 1218 and a second passage 1216 that are in fluid communication, respectively, with steps 1222 and 1220 of pneumatic section 1207.

Exemplary housing 1203 and solenoid 1202 are distributed by MAC Valves as Model Number 44B-L00-GFDA-1KV. Since this is a commercially available product, the operation of the head seals 1217 and the cavity in which it moves are not described in the smallest detail. However, its general operation is described in this document. A constant source of pressurized air is received at the intake port 1212 and is directed to one of the passages 1216 or 1218. The vertical position of the head 1217 determines whether the passage 1216 or 1218 is in communication with the intake port 1212.

For example, if the head 1217 is positioned so that the air is directed from the intake port 1212 through the passage 1216, then it flows into the passage 1220 and into the cavity 1226 below the piston 1230. This air flow will force to piston 1230 to move up. When the piston 1230 moves upward, the air is forced to flow from the cavity 1224 through the passage 1222. With the head 1217 in this position, the air can exit the passage 1222 towards the passage 1218 and out of the first port of escape 1210.

On the contrary, if the air is directed from the intake port 1212 through the passage 1218, then it flows into the passage 1222 and into the cavity 1224 above the piston 1230. This air flow will force the piston 1230 to 40 move down . Thus, the air leaves the cavity 1226 through the passage 1220 and enters the passage 1216. Due to the position of the head, the air can escape from the passage 1216 outside the second exhaust port 1214.

In this manner, solenoid 1202 and head 1217 can be used to move piston 1230 up and down within pneumatic section 1207. Piston 1230 may include one or more o-rings 1232 as depicted in FIG. 12. The pneumatic section 1207 usually includes an open bottom that allows the piston 1230 to be inserted therein. This lower part can be closed with a plug 1228 that can be threaded or otherwise connected to the pneumatic section 1207. Using pressurized air to move the piston 1230 both up and down, the pneumatic section 1207 eliminates the spring represented in other embodiments described in this document. Thus, the movement of the piston 1230 does not have to exceed the force of the spring and, therefore, less force (i.e. volume or air pressure) is needed to move the piston 1230. Also, when the pressure of air changes, the opening and closing forces remain balanced.

According to one embodiment, the solenoid section (1202 and 1203) are integrally formed with the pneumatic section 1207. Due to the juxtaposed arrangement of the integral solenoid and pneumatic housing with the hydraulic section 1205, the solenoid 1202 and the housing 1203 are separated thermally of the high temperatures normally associated with hydraulic section 1205. For example, in the exemplary arrangement of FIG. 12, it was found that the temperature at or near the hydraulic section 1205, during the tests, was approximately 176.67 ° C while the temperature of the coil 1204 was approximately 65.56 ° C. A number of benefits result from this thermal separation. Solenoid 1202 will require less insulation than with conventional dispensing modules and solenoid 1202 will probably be more reliable. Inside accommodation 1203, the 60

Various seals and O-rings can now be constructed of a lower temperature material than conventional hot melt dispensers. Such a material would include rubber, such as a cemented nitrile material that has better friction and wear characteristics than high temperature rubbers such as Viton®.

The piston 1230 advantageously includes a groove 1235 that extends around the center of its periphery into which one end 1234 of the rotating lever arm 1236 will fit. The rotating lever arm 1236 5 extends through the flexible seal 1239 towards a chamber 1252 of the hydraulic section 1205. The rotating lever arm 1236 rotates around a pivot point 1238, as defined by a pin, so that when one end 1234 moves down the other end 1240 moves up, and vice versa. The end 1240 is operatively coupled to a needle 1242 within the hydraulic section 1205. Thus, when the end 1240 moves up or down, the needle 1242 moves up or down as well. 10

In the hydraulic section 1205, a pressurized liquid is received at the intake port 1250 and enters the chamber 1252. If the end 1256 of the needle 1242 fits tightly into the seat 1254, then the liquid remains inside the chamber 1252. If, however, the needle 1242 is raised so that its end 1256 is disengaged, then the liquid is dispensed from the chamber 1252 through the dispensing hole 1243. The needle 1242 can extend through the hole (i.e., null cavity) or partially by it (i.e. reduced cavity). In this embodiment 15, a biasing member, such as a spring 1244, polarizes the needle 1242 downward and, therefore, the movement of the piston 1230 is sufficient to overcome the force of the spring 1244 in order to dispense liquid from hole 1243. Those with basic knowledge in the art will recognize that the polarization member can be configured as a piston having pressurized air on one or both sides of the piston.

The embodiment of FIG. 12A explicitly includes a stroke adjustment mechanism 1246. The mechanism 1246 is a threaded rod that passes through a cover 1248 and can be rotated clockwise or counterclockwise to adjust its distance from the top of the needle 1242. The position of the mechanism 1246 controls the degree to which the needle 1242 can move upwards.

FIG. 13 illustrates another exemplary dispenser that is similar in many respects to the embodiments described above. These similar aspects will be described briefly but without great detail. A hydraulic section 25 1302 is arranged juxtaposed with a pneumatic section 1304 that is coupled to a solenoid 1303. The solenoid 1303 controls the delivery of pressurized air 1306 to a piston 1307 to overcome a spring 1308. The movement of the piston 1307 gives as result of the movement of the rotating lever arm 1310 which rotates around a pivot point 1312 and passing through a flexible seal 1308. The movement of the rotating lever arm 1310 results in the movement of a needle 1327 within the hydraulic section 1302 The movement of the needle 1327 results in the dispensing of liquid or the recirculation of liquid within the hydraulic section 1302. The needle 1327 of this embodiment includes a large diameter portion 1326 and a small diameter portion 1330. The liquid enters the hydraulic section 1302 through an intake port 1328 and is dispensed from the hole 1324, or enters the port of recirculation 1325, depending on the position of the needle 1327.

The piston 1307 must overcome a series of forces to keep the needle 1327 in a closed position. Thus, the exemplary hydraulic section 1302 includes a number of beneficial features to help balance the pressures in the needle 1327. The large diameter head 1314 provides a long flow fitting on the recirculating side that results in a fall. of increased pressure. The small diameter head 1322 provides a short flow fitting on the delivery side which results in an increased flow capacity. The tapering of the head 1322 and the seat 1323 also reduces the flow resistance when the liquid is dispensed. 40

Additional features within this embodiment include the different diameters of the seats 1316 and 1323. The seat 1316 with which the head 1314 is sealed is larger in diameter than that of the seat 1323 with which the head 1322 is sealed. Due to the relationship between force, pressure and area, the large diameter in the seat 1316 provides a relatively large force even under a lower pressure. On the contrary, the small diameter in the seat 1323 provides a relatively smaller force even under a higher pressure. For example, 45 if the seats are of the same diameter and the distribution pressure is 3,447,378.5 Pa, then a fall of 344,737.85 Pa through the recirculation seat 1316 will reduce the force required to seal the delivery side in 10%. However, if the recirculation seat 1316 is sized to be twice the area of the delivery seat 1323, then the same fall of 344,737.85 Pa will reduce the force required to seal the distribution side by 20%. fifty

Elastomer members 1320 and 1318 also provide additional benefits. These members are compressible and can be constructed of an elastomer or similar material that can withstand the heat experienced within the hydraulic section 1302. When the needle 1327 moves upward, the compressible member 1318 expands and therefore reduces the length effective stroke of needle 1327 on the recirculation side. The result is that there is effectively an increase in the pressure drop on the recirculation side. Regardless, the compressible member 1320 is compressed when the needle moves so that the head 1322 and the seat 1323 are sealed. The additional displacement provided by the compressible member 1320 improves the re-aspiration operation of the hydraulic section 1302.

As an example, the distribution side seat 1323 may be designed to close against 3,447,378.5 Pa. If the seat outlet diameter is 1.59 mm, the area is 1.94 mm squares, and the force that 60

Acting down is 6.67 Newtons. If there is a fall of 344,737.85 Pa through the recirculation seat 1316 and it is the same size (i.e., 1.94 square mm), then the force acting upwards is 0.07 Newtons. To close the delivery seat 1323, the piston 1307 must distribute 6.61 newtons of force. If, however, the fall of 344,737.85 Pa is observed through a recirculation seat 1316 that has a diameter of 3.18 mm, then the force acting upward is 2.67 Newtons (i.e. 344,737.85 Pa x 7.74 square mm). In this second case, the piston 1307 must exceed 4 newtons to close the delivery seat 1323. As a result, the net force that the piston 1307 would need to provide to close the distribution seat 1323 has been reduced, compared to whether the diameters of the seats were the same size, approximately 40%.

In an advantageous embodiment in which a piezoelectric actuator element is replaced by the pneumatic actuator element. Heads 1314, 1322 and seats 1316 and 1322 are sized so that the needle 1327 closes (i.e., in recirculation mode) when the actuator is in its neutral state, or de-energized, or, in other words, hydraulic section 1302 has a normally closed delivery valve.

Exemplary embodiments described above included a pneumatic section and a solenoid section that work together to move a piston into the pneumatic section through pressurized air. The present invention is not limited in its use and application to such pneumatic sections only. As an example, FIG. 14 represents a sectional view of an exemplary dispenser having a hydraulic section 1402 juxtaposed with an electrical section 1404. The hydraulic section 1402 includes a chamber 1418 that receives pressurized liquid 1416 from the manifold 1417. Inside the chamber 1418 there is a needle 1420 configured to fit into the valve seat 1421. When the needle 1420 fits into the valve seat 1421, 20 no pressurized liquid travels from the chamber 1418 through the passage 1423 and out of the hole 1424 of the nozzle 1422 However, when the needle 1420 is positioned so that it does not fit into the valve seat 1421, then the pressurized liquid exits the chamber 1418 through the passage 1423.

The electrical section 1404 includes an electromagnetic coil 1406 arranged around an armature 1408 that is polarized downward by a compression spring 1409. In operation, electrical current 25 is supplied to the coil 1406 by a power source (not shown) by the electrical connector 1411, which generates an electromagnetic field between the armature 1408 and a pole 1410 so that the armature 1408 is attracted to the pole 1410. Since the pole 1410 cannot move, the armature 1408 will move against the force of the spring 1409 until I hit the pole 1410.

The armature 1408 of the electrical section 1404 and the needle 1420 of the hydraulic section 1402 are operatively coupled to each other through the swivel lever arm 1430. The arm 1430 includes an end 1436 that engages the armature 1408. For example , the end 1436 can be ball-shaped and fit into a through hole 1437 machined in the armature 1408. Similarly, the other end 1438 of the arm 1430 can be attached to the needle 1420. The seal 1432 is located between the section hydraulic 1402 and electrical section 1404 to prevent the pressurized liquid 1416 from leaking into electrical section 1404. The arm 1430 rotates around a pivot point 1434, 35 as defined by a pin, thus, the downward movement of the armature 1408, as when the electric current is cut to the coil 1406 and the spring 1409 polarizes the armature 1408 downwards, results in an upward movement of the needle 1420. By the contr Aryan, the upward movement of the armature 1408, such as when electric current is supplied to the coil 1406 and the armature 1408 is attracted to the pole 1410, results in a downward movement of the needle 1420. 40

Those with basic knowledge in the art will appreciate that different configurations of electrical section 1404 can be used in the invention. For example, the electrical section 1404 can be modified such that the needle 1420 normally closes when no electric current flows to the coil 1406. Additionally, those with basic knowledge in the art will recognize that an electric actuator, such as the electrical section 1404 , can be used with the various embodiments of the hydraulic sections shown and described in this document.

Alternatively, piezoelectric actuators that resemble up and down movement of a piston can also be used. Such electrically operable pistons can be coupled to a rotating lever arm similar to that described herein without departing from the scope of the present invention. As such, the electrical section (which replaces the pneumatic section) can be arranged juxtaposed with the hydraulic section 50 in order to provide the benefits and advantages described herein. The present invention also contemplates the use of hydraulic sections that include additional air admissions commonly referred to as "process air." Such air is separated from that of the pneumatic section and can be used, as someone with basic knowledge would appreciate, to adjust the way in which the liquid is dispensed from the dispensing orifice.

Although the present invention has been illustrated by a description of various preferred embodiments and although these embodiments have been described in some detail, it is not the intention of the Applicants to restrict or limit the invention in any way to such detail. Advantages and additional modifications will easily arise for those skilled in the art. The various features of the invention can be used alone or in numerous combinations depending on the needs and preferences of the user as long as they fall within the scope of the claims. This has been a description of the present invention, together with the preferred methods of practicing the present invention as is currently known.

Claims (21)

1. A dispenser, comprising:  an actuator section (104) having a first movable member (108);  a hydraulic section (102) coupled to said actuator section (104) and having a second movable member (110), adapted said hydraulic section (102) to dispense a liquid from an outlet (122) and adapted said actuator section (104) to control the dispensing of the liquid; 5  a rotating lever arm (230) having a first end (236) operatively coupled to said first movable member (108) in said actuator section,  and which further includes a second end (238) operatively coupled to said second mobile member (110) in said hydraulic section (102), wherein said first mobile member (108) is operative to move said second mobile member (110 ) between the open and closed positions to start and stop respectively the flow of liquid from said outlet (122),  characterized in that a flexible non-diaphragm seal (232) is positioned between said hydraulic section (102) and said actuator section (104) and adapted to prevent the liquid from seeping into said actuator section (104); and because said rotating lever arm (230) extends from said first end (236) through said seal (232) and towards said hydraulic section (102). fifteen 2. The dispenser of claim 1, wherein said hydraulic section (102) is coupled to said actuator section (104) in a juxtaposed configuration 3. The dispenser of claim 1, wherein said actuator section (104) comprises a pneumatic section wherein said first movable member (108) is a piston adapted to move in response to pressurized fluid. twenty 4. The dispenser of claim 1, wherein said actuator section (104) comprises an electrical section wherein said first movable member (108) is an armature adapted to move in response to an electrical signal. 5. The dispenser of claim 1, further comprising:  a solenoid adapted to deliver pressurized fluid to said pneumatic section. 25 6. The dispenser of claim 1, wherein said swivel lever arm (230) includes a fixed pivot point. 7. The dispenser of claim 1, wherein said swivel lever arm (230) includes a pin adapted to define a fixed pivot point around which said swivel lever arm (230) rotates. The dispenser of claim 1, wherein the movement of said first mobile member (108) in a first direction moves said second mobile member (108) towards the open position and the movement of said first mobile member (108) in a second direction moves said second movable member (108) towards the closed position. 9. The dispenser of claim 1, wherein said hydraulic section (102) includes an operating polarization member for polarizing said second movable member (108) towards the closed position. 10. The dispenser of claim 1, wherein said seal (232) is not restricted along a periphery 35 of said seal (232). 11. The dispenser of claim 1, wherein said seal (232) is adapted to withstand working pressures from approximately 551,580 Pa (80 psi) to approximately 10,342,000 Pa (1,500 psi). 12. The dispenser of claim 1, wherein said seal (232) is adapted to withstand working pressures from approximately 1,379,000 Pa (200 psi) to approximately 10,342,000 Pa (1,500 psi). 40 13. The dispenser of claim 1, wherein said seal (232) is adapted to withstand working pressures from approximately 2,068,400 Pa (300 psi) to approximately 6,205,300 Pa (900 psi). 14. The dispenser of claim 1, wherein said seal (232) is adapted to withstand working pressures from approximately 2,757,900 Pa (400 psi) to approximately 5,515,800 Pa (800 psi). 15. The dispenser of claim 1, wherein said swivel lever arm (230) has a pair of 45 opposite ball-shaped ends and a pin disposed therebetween adapted to define a fixed pivot point and said arm of rotating lever (230) passing through said seal (232). 16. The dispenser of claim 15, wherein said actuator section (104) comprises a section pneumatic in which said first movable member (108) is a piston adapted to move in response to pressurized fluid. 17. The dispenser of claim 15, wherein said actuator section (104) comprises an electrical section wherein said first movable member (108) is an armature adapted to move in response to an electrical signal. 5 18. The dispenser of claim 1, wherein said second movable member (108) is a self-aligning needle. 19. The dispenser of claim 1, wherein said hydraulic section (102) is configured to operate in at least one of a re-aspiration mode and a three-way mode. 20. The dispenser of claim 1, wherein said actuator section (104) comprises:  a solenoid; Y  a pneumatic section having said first mobile member (108) and coupled to said solenoid, said solenoid adapted to deliver pressurized fluid to said pneumatic section to move said first mobile member (108);  said actuator section (104) coupled to said hydraulic section (102) in a juxtaposed configuration 15 such that said pneumatic section is located substantially between said hydraulic section (102) and said solenoid. 21. Dispenser of claim 1,  wherein a bushing support is coupled to said rotating lever arm (230) and adapted to withstand said seal (232), said bushing support positioned radially into a periphery of said seal (232).