JP2005508011A - 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

【Technical field】
[0001]
[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.
[0002]
[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.
[Background]
[0003]
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 fabrication, castings, tooling and machinery and equipment fabrication and assembly. Applied to a wide variety of industries such as SMT repair, various other uses.
[0004]
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.
[0005]
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.
[0006]
[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.
[0007]
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).
BEST MODE FOR CARRYING OUT THE INVENTION
[0008]
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.
[0009]
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.
[0010]
The valve block can be constructed of stainless steel or other suitable material and, in the preferred embodiment, has a tapered bore 18 in which there is a tilted directional valve. This is because 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.
[0011]
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
[0012]
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.
[0013]
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.
[0014]
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.
[0015]
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.
[0016]
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.
[0017]
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.
[0018]
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.
[0019]
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.
[0020]
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.
[0021]
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.
[0022]
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.
[Brief description of the drawings]
[0023]
FIG. 1 is a front view of a cross section of a measuring valve constructed according to the principle of the present invention.
FIG. 2 is a partial cross-sectional view similar to FIG.
3 is a partial cross-sectional side view of the measurement valve illustrated in FIGS. 1 and 2. FIG.
FIG. 4 is a plan view of a single measuring rod constituting a part of the present invention.
FIG. 5 is a view of the end of the measuring rod shown in FIG. 4;
FIG. 6 is a rear view of a valve block constituting a part of the present invention.
FIG. 7 is a side view of the valve block illustrated in 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.
10 is a cross-sectional view of the valve block illustrated in FIGS. 6-9 taken along line 10-10 of FIG.
FIG. 11 is a schematic plan view of a directional valve constituting a part of the present invention.
12 is a view of the end of the directional valve shown in FIG. 11. FIG.
13 is a cross-sectional view taken along line 13-13 of FIG.
[Explanation of symbols]
[0024]
10 ... Measurement valve 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 ... Measuring rod 36 ... Measuring chip 37 ... Measuring chamber 38 ... Injection port 40 ... Injector mounting bracket 42 ... Motor 44 ... Drive gear 46 ... Flat / play gear 48 ... Thrust washer 50 ... Tooth 52 ... Switch plate

Claims (2)

A valve that measures continuous linear positive displacement,
Two chambers for distributing fluid;
A measuring rod disposed in each of the two chambers, each measuring rod having a measuring chip for pressurizing a fluid contained in the respective fluid distribution chamber, the two measuring rods Is a measuring rod movable in two opposing linear directions;
A fluid injection port that selectively permits the inflow of fluid into each of the two fluid distribution chambers;
A motor that linearly drives the two measuring rods in a linear direction facing each other simultaneously;
A switch for reversing the operating direction of the motor, thereby reversing the respective linear movement direction of each of the measuring rods;
A valve that measures continuous linear positive displacement, comprising a directional valve that alternately distributes fluid from each of the two fluid distribution chambers according to the direction of operation of the motor. A method of continuously distributing fluid from a linear positive displacement measuring valve,
The first measuring rod disposed in the first bore is linearly driven upward,
A fluid dispensing chamber is filled with fluid to be dispensed by fluid communication with the first bore;
The second measuring rod is driven linearly downward simultaneously with the driving of the first measuring rod,
When the upper end of the first measuring rod reaches the upper limit, the linear directions of the movement of the first and second measuring rods are reversed, whereby the first measuring rod is linearly lowered. A method of continuously dispensing fluid from a linear positive displacement measuring valve that begins to move to, thereby pressurizing the fluid dispensing chamber and dispensing fluid from the chamber.

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