JP4164029B2 - Valve that measures continuous positive displacement - Google Patents

Abstract

A continuous operation metering valve, based on true volumetric positive displacement technology, uses an innovative dual rack and drive pinion design that enables the valve (34) to dispense from one meter chamber (32) while the other meter chamber (32) is filling. This provides greater dispense cycle rates because it does not require a fill or reload period. With an optional encoder-controlled motor (42), the inventive metering valve is capable of almost unlimited precision dispensing with "on-the-fly" adjustment capability. The metering valve is easily disassembled and cleaned, using stainless steel wetted path components and Teflon seals for the widest range of chemical compatibility. An integral electronic board, mounted to the side of the valve, may be utilized to control the 4-way directional valve and motor direction (when not using a rotary encoder control).

Description

[Related prior applications]
This application claims benefit under 35 USC 119 (e) as of the filing date of provisional application serial number 60/198594 filed on April 19, 2000, which is hereby incorporated by reference Explicitly incorporated by reference.

[Background of the present invention]
The present invention relates to a continuous positive displacement measuring valve, and more particularly to an improved linear measuring valve, which can be used while the other measuring chamber is full. Has two innovative rack and pinion designs that allow dispensing from one measurement chamber.

Microvalves repeatedly and accurately dispense fluid materials such as adhesives, epoxies, potting mixtures, SMT adhesives, two-part adhesives, and solder paste (with solids dispersed therein) Known in the prior art.
Typically, these distributions for fluid materials are used in assembly and repair of electronic devices, molds in place gaskets, assembly and sealing of components, mold making, castings, tooling and machinery and equipment fabrication and assembly. Applied to a wide variety of industries such as SMT repair, various other uses.

  An existing positive displacement dispensing system of this type is of rotary construction, for example the valve disclosed in US Pat. No. 5,931,355, which is hereby expressly incorporated herein by reference. And generally assigned with this application. Therefore, these dispensing systems are not truly based on volumetric positive displacement techniques.

Utilize a metering valve based on true volumetric positive displacement technology that allows the valve to dispense from the first metering chamber while the second metering chamber is full and vice versa This would be advantageous for at least some dispensing applications.
The result will be a continuous operating cycle with a higher dispensing cycle rate due to the lack of a need for a full or reload period.

[Outline of the Invention]
The present invention has a continuously actuated measuring valve based on truly volumetric positive displacement technology.
Unlike traditional metering valves, the ingenious valve applies an innovative dual rack and drive pinion design, which is designed so that one metering chamber is filled while the other metering chamber is full. Allows the valve to dispense from. This provides a greater dispensing cycle rate since no filling or refilling period is required. With the selective use of an encoder-controlled motor, the inventive valve according to the invention can be distributed with almost infinite accuracy due to its “on-the-fly” adjustment capability.

The metering valve is easily disassembled and cleaned using a Teflon seal for the widest chemical compatibility with stainless steel wet passage parts.
An integrated electronic board mounted on the side of the valve can be used to control the direction of the unique 4-way directional valve and motor (when not using rotary encoder control).

DESCRIPTION OF PREFERRED EMBODIMENTS
The invention, together with additional features and advantages thereof, are best understood by referring to the following description taken in conjunction with the accompanying schematic drawings.

  Referring more particularly to the drawings, FIGS. 1-3 show a continuous measuring valve 10 constructed in accordance with the principles of the present invention. The measurement valve 10 is advantageously configured in a modular manner and includes a valve block 12, a measurement block 14, and a motor block 16.

The valve block 12 can be constructed of stainless steel or other suitable material, and in a preferred embodiment, has a tapered bore 18 in which it has a tilted directivity. This is because the valve 20 is inserted. The directional valve 20 preferably comprises a four-way inclined seat valve, which is of known construction and is secured in the bore 18 using a nut and washer assembly 22. However, alternatively, for example, a four-way cylindrical seat valve and a corresponding cylindrical bore can be utilized, and the use of other known directional valve configurations is also within the scope of the present invention. It is.

  The directional valve 20 is, in the illustrated embodiment, driven using a pivot arm 24 (FIG. 3), which is done in turn depending on the pivot plate 26. The air cylinder 28 is utilized to drive the pivot plate 26 in response to driving of a solenoid valve (not shown) that is sequentially driven by commands from a control circuit / switch 30 or other suitable means. The

  The metering block 14 can also be constructed from stainless steel or other suitable material. A set of bores 32 in the measurement block 14 is adapted to accommodate a corresponding measurement rod of the set of measurement rods 34. Each of the set of measuring rods 34 includes a respective measuring tip 36, which is particularly adapted to apply a displacement pressure to the fluid contained in the bore 32 and its corresponding measuring chamber 37. Is done.

Such fluid is the fluid to be dispensed, as described above in the technical background part of the present application, for example, adhesives, epoxies, potting mixtures, SMT adhesives, two part adhesives, and solder pastes (As well as solids dispersed therein) and other desired fluids.
Fluid is introduced into the valve 10 via a fluid injection port 38, which preferably has a female luer lock or a 10-32 inlet.
A syringe mounting bracket 40 can be used to accommodate an industrial injector containing fluid to be dispensed and introduced into the valve through the injection port 38. . Typically, such an injector has a fluid capacity of up to 35 cc.

In connection with the motor block 16, this housing element can be constructed of tool steel, for example with a hard chrome finish plating to provide improved wear resistance. Is possible. Mounted on the motor block 16 is a motor 42, which in one preferred embodiment may have a 6 watt, 24V DC gear motor.
The motor 42 drives a drive gear 44 within the motor housing 16 that includes a spur / idler gear 46 and a thrust washer 48.

  The upper end of the measuring rod 34 is better visible in FIG. 4 and is configured as a rack in a rack and pinion system. In other words, the outer periphery of the measuring rod 34 at this site has teeth 50 that are adapted to mesh with corresponding teeth on the outer periphery of the drive gear 44, so that in a rack and pinion system, the motor 42. The rotation of the drive gear 44 by means of a linear actuation of the measuring rod 34 above and below.

  Advantageously, rotation of the motor 42 in the first direction is accomplished by moving each measuring rod 34a and 34b linearly in the opposite direction, one moving upward and the other moving downward. When the measuring rods 34a and 34b that move upward come into contact with the switch plate 52 disposed at the upper end of the motor block 16, the limit switch is driven, which in turn reverses the direction of the motor 42. Then, the measuring rod 34a that has moved upward starts to move downward, and the measuring rod 34b starts to move upward.

  In operation, a control signal for the drive motor 42 rotates the drive gear 44, which in turn pushes one of the two racks or two measuring rods 34 in the distribution direction (downward) and fills the other. Press in the direction (upward) in order. The two measuring rods 34 are assembled with a cup seal and a fluid seal to provide chemical compatibility. This linear rack movement results in fluid displacement on the positive volume. A low voltage signal to the motor 42 results in a low distribution ratio. The small voltage signal results in a small shot size.

  Each side of the two metering chamber valves holds a fluid volume of 1 cc, but smaller or larger volume metering valves may be suitable for certain applications. When one measurement chamber 37 and the bore 34 are empty, the limit switch on the switch plate 52 reverses the polarity of the motor and starts distribution from the other measurement chamber. Concurrent with the reversal of the polarity of the motor, the valve 20 is driven into alternating positions, whereby the other measuring chamber is established in fluid contact with the fluid outlet 54, which is preferably And have a male luer lock.

  A rotary encoder on the motor 42 can provide a closed loop signal that rotates the motor in a controlled discrete angular movement that results in an accurate linear displacement.

  A particular benefit of the present invention is that system components can be easily disassembled for easy maintenance and cleaning. Only three screws need to be removed to complete the decomposition. Once disassembled, the bore need only be brushed to clean it.

In other embodiments, a disposable passage modification may be used for the original metering valve, where the metering block and valve block assembly is made of low cost injection mold plastic. Such as when the two-part material is assembled, or when it is not safe to clean, such as containing hazardous materials, or such an assembly is There is no need for price effects.
Stepper motors can be utilized if required. In addition, an improved version of the microshot can be utilized using a special coupling design, in which a smaller measuring rod tip is attached to a standard measuring rod.

  Accordingly, although exemplary embodiments of the invention have been shown and described, many changes, modifications and substitutions may be made by those skilled in the art without departing from the spirit of the invention and the scope of the claims. is there.

It is a front view of the cross section of the valve for a measurement comprised based on the principle of this invention. FIG. 2 is a partial cross-sectional view similar to FIG. 1. FIG. 3 is a partial sectional side view of the measuring valve illustrated in FIGS. 1 and 2. It is a top view of the measuring rod single-piece | unit which comprises a part of this invention. It is a figure of the edge part of the measuring rod shown in FIG. It is a rear view of the valve block which comprises a part of this invention. FIG. 7 is a side view of the valve block illustrated in FIG. 6. FIG. 8 is a front view of the measurement block shown in FIGS. 6 and 7. FIG. 9 is a cross-sectional view of the valve block illustrated in FIGS. 6-8 taken along line 9-9 of FIG. FIG. 10 is a cross-sectional view of the valve block illustrated in FIGS. 6-9 taken along line 10-10 of FIG. It is a schematic plan view of the directional valve which comprises a part of this invention. It is a figure of the edge part of the directional valve shown by FIG. FIG. 13 is a cross-sectional view taken along line 13-13 of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Valve for measurement 12 ... Valve block 14 ... Measurement block 16 ... Motor block 18 ... Inclined bore 20 ... Inclined directional valve 22 ... Nut / washer assembly 24 ... Axis arm 26 ... Axis plate 28 ... Air cylinder 30 ... Control Circuit / Switch 32 ... A set of bores 34 ... Measurement rod 36 ... Measurement chip 37 ... Measurement chamber 38 ... Injection port 40 ... Injector mounting bracket 42 ... Motor 44 ... Driving gear 46 ... Flat / play gear 48 ... Thrust washer 50 ... Teeth 52 ... Switch plate

Claims (8)

A positive displacement dispensing system for dispensing adhesive on a working surface,
A measurement block having first and second bores;
A valve block connected to the measurement block and having first and second measurement chambers, the first measurement chamber having a smaller cross-sectional area than the first bore and communicating with the first bore; The second measurement chamber has a smaller cross-sectional area than the second bore and a valve block communicating with the second bore;
First and second measuring rods disposed in the bore and reciprocatingly moved therein, the first and second measuring rods having a first measuring piece at one end and a first rack in the other end direction. A first measuring rod, a second measuring rod having a second measuring piece at the tip and a second rack in the direction of the other end;
A motor meshing with the first and second racks, wherein the motor is linearly displaced in a direction in which the first and second measuring rods are simultaneously opposed and distributed and refilled by angular displacement of the motor;
A motor controller configured to accurately control the angular displacement of the motor;
Have
A positive displacement dispensing system, wherein the system is configured to dispense adhesive through a fluid outlet. The positive displacement system further comprises an adhesive source, wherein the adhesive is an adhesive selected from the group of epoxy resin, potting mixture, SMT adhesive, two part adhesive or solder paste. The described positive displacement distribution system. The positive displacement distribution system according to claim 1, wherein the positive displacement system further includes a directional valve that allows the first and second measurement chambers and the fluid outlet to selectively communicate with each other. The positive displacement system further includes fixing means for fixing the measurement block, the motor block, and the valve block so that they can be removed from each other. The positive displacement distribution system according to any one of claims 1 to 3, wherein, in order to clean the measurement chamber and the directional valve, the fixing means is operated so as to be easily separated from each other. The positive displacement distribution system according to claim 4, wherein the fixing means includes a screw. The positive displacement distribution system according to any one of claims 1 to 5, wherein the valve block is formed of stainless steel or plastic. The positive displacement distribution system according to any one of claims 1 to 6, wherein the measurement block is formed of stainless steel or plastic. The positive displacement distribution system according to any one of claims 1 to 7, wherein the positive displacement system includes a gear in the motor block and engages the first and second racks and the motor.

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