WO1995004613A1

WO1995004613A1 - Dispenser valve system

Info

Publication number: WO1995004613A1
Application number: PCT/US1994/008910
Authority: WO
Inventors: Charles Oberhauser; Robert Teicher
Original assignee: Fluid Management Limited Partnership
Priority date: 1993-08-10
Filing date: 1994-08-03
Publication date: 1995-02-16
Also published as: AU7557294A

Abstract

A dispenser valve system (10, 12) includes a valve body (30) including a delivery passage (36); a sealing device (60) at one end of the passage (36); a valve mechanism (46, 48, 49) at the other end of the passage; and an input device (70) interconnected with the passage (36) between the sealing device (60) and the valve mechanism (46, 48, 49) for supplying the medium to be dispensed. The valve mechanism (46, 48, 49) includes a valve seat at the end of the passage; a passage extension cylinder (110) extending beyond the valve seat (46); and the valve mechanism (46, 48, 49) including a valve element (48) for engaging the seat (46), and a valve element extension piston (116) extending beyond the seat (46) and into the passage extension cylinder (110) when the valve element (48) is closed against the valve seat (46) for clearing residual undispensed medium; and an actuator (86, 88) for retracting the valve element (48) from the seat (46) to dispense the medium and for engaging the valve element (48) with the seat (46) to end the dispensing.

Description

DISPENSER VALVE SYSTEM FIELD OF INVENTION This invention relates to an improved dispenser valve system for dispensing measured amounts of a medium such as paint pigment or the like.

BACKGROUND OF INVENTION

Conventional fluid dispensing devices such as those used to dispense pigment in paint mixing systems are generally not extremely volumetrically accurate as regards the amount of medium dispensed. The valve mechanisms which do not cut off the flow of the medium at the delivery tip leave uncontrolled residual amounts of the medium in the tip beyond the valve. These uncontrolled amounts can release unexpectedly at any time completely destroying any accurate measurement of the dispensed medium. Further, when the uncontrolled amounts of medium beyond the valve dry and harden they are difficult to remove and can cause random, high-pressure spraying of the medium. SUMMARY OF INVENTION

It is therefore an object of this invention to provide an improved dispenser valve system.

It is a further object of this invention to provide an improved dispenser valve system which is more volumetrically accurate.

It is a further object of this invention to provide an improved dispenser valve system which minimizes or eliminates the amount of residual uncontrolled medium. It is a further object of this invention to provide an improved dispenser valve system which minimizes or eliminates the blockage formed from the drying and hardening of residual medium.

It is a further object of this invention to provide an improved dispenser valve system which minimizes or eliminates random high pressure spraying due to blockage in the dispenser. The invention results from the realization that a truly effective dispenser valve system which is accurate and which avoids blockage of the dispenser and high pressure random spraying can be achieved by providing at the end of the delivery passage a valve seat which receives a valve element, the valve element having a valve element extension piston which extends beyond the valve element and cooperates with a passage extension cylinder to clear residual undispensed medium from the downstream side of the valve seat.

This invention features a dispenser valve system including a valve body having a delivery passage and sealing means at one end of the passage. There is a valve mechanism at the other end of the passage and an input device interconnected with the passage between the sealing means and the valve mechanism for supplying the medium to be dispensed. The valve mechanism includes a valve seat at the end of the passage and a passage extension cylinder extending beyond the valve seat. A valve member includes a valve element for engaging the seat and a valve element extension piston extending beyond the seat and into the passage extension cylinder when the valve element is closed against the valve seat for clearing residual undispensed medium. There are actuator means for retracting the valve element from the seat to dispense medium and for engaging the valve element with the seat to end the dispensing.

In a preferred embodiment the valve element extension piston may be at least coextensive with the passage extension cylinder when the valve element is engaged with the valve seat. The valve element extension piston may extend beyond at least a portion of the passage extension cylinder when the valve element is engaged with the valve seat. The valve element extension piston may be withdrawn clear of the valve seat when the valve element is retracted from the valve seat. The valve seat may be beveled, the valve element may be beveled to conform to the valve seat, and the valve seat and valve element may be beveled at 45°. The valve element extension piston may be chamfered at its distal end. The sealing means may include a diaphragm seal. The valve element extension piston and the passage extension cylinder may have minimum clearance for providing a further valve sealing. DISCLOSURE OF PREFERRED EMBODIMENT Other objects, features and advantages will occur to those skilled in the art from the following description of a preferred embodiment and the accompanying drawings, in which:

Fig. 1 is a schematic diagram of a number of dispenser valve systems according to this invention installed in a dispenser head in a paint dispensing system;

Fig. 2 is an enlarged detailed cross-sectional view of one of the dispenser valve systems shown in Fig. 1;

Fig. 3 is a greatly enlarged detailed schematic diagram of the valve mechanism of the dispenser valve system of Fig. 2 with the valve in the closed position;

Fig. 4 is a greatly enlarged detailed schematic diagram of the valve mechanism of the dispenser valve system of Fig. 2 with the valve in the open position; and Fig. 5 is a schematic block diagram of an overall dispenser system using the dispenser valve system according to this invention.

There are shown in Fig. 1 two dispenser valve systems 10 and 12 according to this invention mounted in a dispenser head 14 which forms a part of a larger dispenser system for dispensing pigment in a paint mixing machine for example. Dispenser valve systems 10 and 12 are mounted to dispenser head 14 by means of integral tabs 16 and 18 and mounting screws 20 and 22. Dispenser valve system 10, Fig. 2, includes a valve body 30 having a head 32, cap 34 and delivery tube 36. Delivery tube 36 fits snugly in bore 38 of dispenser head 14 and is sealingly engaged therewith by means of 0 ring 40. Lower chamber 42 is formed between 0 ring 40 and the lower tip 44 of delivery tube 36. Chamber 42 extends to the bottom of bore 38, where it ends at valve seat 46 and dispensing port 48. Valve seat 46 forms a valve mechanism 49 in combination with valve element 50 which is fixed to move with valve rod 52, centrally located within and spaced from the inner walls of delivery tube 36. The upper end of delivery tube 36 is integral with bore 54 in head 32. Bore 56 in head 32 extends from delivery tube 36 up to diaphragm seal 60. There is thus formed passage 62 which has at one end diaphragm seal 60 and includes bore 56, internal passage and delivery tube 36, and chamber 42. The lower end of passage 62 ends at valve mechanism 49.

Diaphragm seal 60 is mounted in place between cap 34 and head 32 of valve body 30 for example by means of screws, not shown. Diaphragm seal 60 permits an extremely tight seal to be made around valve rod 52 so that no air can leak into passage 62 nor any of the dispensed medium can be lost from passage 62. This contributes to the volumetric accuracy of valve system 10. The use of diaphragm seal 60 also reduces friction and thus allows faster and easier operation and less wear than would be encountered, for example, were an O ring to be used. Between diaphragm seal 60 and valve mechanism 49 there is interconnected with passage 62 an input port 70 through which precisely measured amounts of the medium to be dispensed are introduced. Thus if one ounce of medium is to be dispensed by valve mechanism 49, one ounce of medium would be introduced under pressure at input nozzle 70. Rod 52 carries a spider 72 that is an open structure that keeps rod 52 centered in bore 38 but does not interfere with the flow of the medium in chamber 42, which is controlled by valve mechanism 49. Other centering means could be built into the valve body, the tube, or the centering means could be an integral feature of the rod. Above diaphragm seal 60 and cap 34, rod 52 carries keeper plate 80 held in place by a retaining ring 82 that supports spring 83, which at its upper end is positioned by the lower face 84 of solenoid 86. Spring 83 surrounds armature 88 of solenoid 86, and rod 52 is fixed to armature 88 by means of roll pin 90. Valve body 30 and solenoid 86 are rigidly attached to one another by brace 92 using upper and lower cap screws 94 and 96, respec¬ tively. In operation, when dispensing is called for a predetermined amount of medium is introduced into input nozzle 70. Solenoid 86 is actuated to retract rod 52 and open valve mechanism 49 for a predetermined period of time. When that time has expired, solenoid 86 is de-energized and spring 83 drives rod 52 downwardly so that valve element 48 engages valve seat 46 to close the valve and end the dispensing activity.

The construction of the valve mechanism can be seen in greater detail in Fig. 3, where valve mechanism 49 is shown to include valve element 48 and where it can be seen that valve seat 46 is generally conical in shape and is beveled at 30-60°, and preferably 45°. Valve element 48 includes a conforming beveled surface 100 which is also inclined at an angle of 45°. There is a valve element extension cylinder 110 that extends below valve seat 46 to the dispensing port 112 in the lower face 114 of dispenser head 14. A valve element extension piston 116 extends into cylinder 110 and may extend even beyond cylinder 110 such as shown at portion 118. The distal end of piston 116 may be chamfered as shown at 120 or otherwise contoured. Piston 116 is typically very closely sized to cylinder 110 so that it acts as an additional seal to valve seat 46 and valve element 48 as well as operating to clear residual undispensed medium from cylinder 110. For example, with piston 116 having a diameter of .156 inch, cylinder 110 may have a diameter of .160 inch. In this particular embodiment the valve system is cylindrically symmetrical about a central axis and the cylinder has a circular cross-sectional area, but this is not a necessary limitation of the invention.

In the retracted mechanism, when valve element 48 is moved away from seat 46 so that valve mechanism 49 is opened, there is sufficient clearance for the medium to flow around valve element 48 and piston 116 and flow unimpeded through cylinder 110 and out port 112. To provide this there should be a sufficient retraction stroke, for example a quarter- of an inch, when piston 116 is for example a tenth of an inch or so in length.

Although in the specific embodiment described, dispenser valve systems 10 and 12 have been shown inclined so that bore 110 is at an angle to surface 114 and port 112 actually has an elliptical cross section, this is not necessarily a limitation of the invention; it is due to the shape of dispenser head 14. Dispenser valves 10 and 12 may in accordance with this invention be operated at any angle including a straight-up vertical position wherein dispensing is perpendicular to lower surface 114. The timing and operation of dispenser valve system 10 may be controlled by a computer or micro¬ processor 140, Fig. 5, which operates a volumetric source 142 such as a screw feed stepper motor driven volumetric source 142, which is capable of outputs to an accuracy of 1/4500 of an ounce, for example. Using such a device, dispenser valve system 10 can produce accuracies of 1/384 of an ounce, and even 1/1000 of an ounce. As the proper volume of medium is being delivered by volumetric source 142 to input port 70, computer port 140 operates timer 144 synchronously to energize solenoid 86 for a predetermined period of time, providing the proper open dwell time for valve mechanism 49 so that the precise measured amount of paint pigment or other medium can be dispensed. At the end of that time period, solenoid 86 is de-energized and spring 83 returns valve mechanism 49 to the closed position. Although specific features of this invention are shown in some drawings and not others, this is for conven¬ ience only as each feature may be combined with any or all of the other features in accordance with the invention. Other embodiments will occur to those skilled in the art and are within the following claims:

Claims

What is claimed is:

1. A dispenser valve system comprising: a valve body including a delivery passage; a sealing means at one end of said passage; a valve mechanism at the other end of said passage and an input device interconnected with said passage between said sealing medium and said valve mechanism for supplying the medium to be dispensed; said valve mechanism including a valve seat at the end of said passage, a passage extension cylinder extending beyond said valve seat, and a valve member including a valve element for engaging said seat and a valve element extension piston extending beyond said seat and into said passage extension cylinder when said valve element is closed against said valve seat for clearing residual undispensed medium; and actuator means for retracting said valve element from said seat to dispense the medium and for engaging said valve element with said seat to end the dispensing.

2. The dispenser valve system of claim 1 in which said valve element extension piston is at least coextensive with said passage extension cylinder when said valve element is engaged with said valve seal.

3. The dispenser valve system of claim 1 in which said valve element extension piston extends beyond at least a portion of said passage extension cylinder when said valve element is engaged with said valve seal.

4. The dispenser valve system of claim 1 in which said valve element extension piston is withdrawn clear of said valve seat when said valve element is retracted from said valve seat.

5. The dispenser valve system of claim 1 in which said valve seat is beveled.

6. The dispenser valve system of claim 5 in which said valve element is beveled to conform to said valve seat.

7. The dispenser valve system of claim 1 in which said valve seat and element are beveled at 45°.

8. The dispenser valve system of claim 1 in which said valve element extension piston is chamfered at its distal end.

9. The dispenser valve system of claim 1 in which said sealing means includes a diaphragm seal.

10. The dispenser valve system of claim 1 in which said valve element extension piston and said passage extension cylinder have minimum clearance for providing a further valve sealing.