Viscous fluid metering device

Abstract

A metering device having two gears and a center plate defining a gear chamber having two major lobes to receive the gears, each of the major lobes defining a diameter and a circular segment having a perimeter extending greater than one hundred eighty degrees. The face surfaces of the first gear, the second gear and the center plate are each machined to be as precisely flat as practical and to be as precisely of equal thickness as practical. The first gear and the second gear are trued on an arbor to eliminate as much runout as practical while at the same time reducing a diameter of the first gear and the second gear to be the substantially the same or slightly larger than the diameter of the major lobes. The first gear and the second gear are press fit into the major lobes; and lapped in the major lobes.

Description

CLAIM TO PRIORITY [0001] This application is a continuation of U.S. patent application Ser. No. 10 / 794,175 which claims priority to U.S. Provisional Applications Ser. Nos. 60 / 452,606 entitled “Quick Change Nozzle” filed Mar. 6, 2003 and 60 / 454,275 entitled “Gear Pump Case” filed Mar. 13, 2003, the entire contents of the foregoing are incorporated herein by this reference. RELATED APPLICATIONS [0002] This application is related to U.S. Provisional Application Ser. No. 60 / 452,209 filed Mar. 5, 2003 entitled “System and Process for Glazing Glass to Windows and Door Frames” and to Utility Application filed on Mar. 5, 2004, with the same title, having Attorney Doc. No. 1843.02-US-02, the entire contents of which are incorporated herein by this reference.FIELD OF THE INVENTION [0003] This invention relates to dispensing viscous fluids prone to hardening, such as sealants, and more particularly relates to a metering device and nozzle for dispensing viscous fluids. BACKGROUND OF THE INVENTI...

AI Technical Summary

Benefits of technology

[0016] It would be desirable to have a durable metering device that has minimal leakage and a quick disconnect nozzle assembly that can be rapidly connected and disconnected and fitted onto the nozzle holder manually without the use of a tools. Preferably the nozzle assembly should provide a leak-proof connection with the fluid source that can be easily positioned in a preferred orientation. The assembly should be easily inspected, have few moving parts and easily replaceable sealing members. In addition, the nozzle assembly should allow for repeatable positioning of the nozzle.

[0018] Another trend seen in the adhesives industry is toward the use of two part catalyzed sealants. Two part catalyzed sealants also include high levels of abrasive and corrosive components. These qualities accelerate wear on dispensing system components. Thus, both durability and ease of maintenance are important qualities for equipment used to dispense these types of sealants.

[0019] While it is desirable, in hot applied sealant systems, to maintain the fluid passage ways at a high temperature in order keep the sealants fluid, it is undesirable to expose mechanical components such as servo motors, gear boxes and actuators to high temperatures. Exposing these components to elevated temperatures tends to accelerate wear and increase the likelihood of early component failure.

[0020] The present invention solves many of the above problems by providing a robust gear metering device and an easily changeable nozzle and holder assembly.

[0022] The invention includes a gear metering device suited to delivering viscous fluids such as sealants and desiccants used in the window manufacturing industry. The metering device includes a gear metering device chamber enclosed within metering device body assembly and transfers fluid under pressure to the outlet of the metering device. A significant feature of the present invention is that the surface finish of the gear teeth and clearances between gear teeth and the walls of the metering chamber are held to tight tolerances so that pressure generated by the motion of the gears is not dissipated through leak paths in the metering chamber. Another significant feature of the present invention is the use of materials of construction and seals uniquely adapted to resist deterioration under contact with the abrasive and caustic chemicals in sealants.

Problems solved by technology

The ease of replacement of a nozzle can significantly affect machine utilization.

A further problem encountered with hot applied sealants is when they are subjected to high pressures, solids in the hot applied sealant mix will tend to come out of suspension.

For example, if a hot applied sealant material can only be subjected to a maximum pressure of 2,500 psi and there is a pressure loss passing through the passageways of the system of 1,000 psi, this can create a major problem in maintaining high enough levels of pressure in the lowest pressure areas of the system while keeping high pressure areas below the critical pressure.

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