Unit Instruments, Inc.

Randall J Vavra

Michael J Doyle

Kim Ngoc Vu

Lam T Nguyen

Erik Q Tran

A liquid flow controller for metering a flow of liquid has an inlet to receive the liquid. The inlet feeds the liquid to a high resistance liquid flow path across which a pressure drop arises. A pressure sensor measures the liquid flow induced pressure drop and generates pressure drop signal which is fed to an electronic circuit. A temperature sensor is connected to the high resistance liquid flow path and generates a temperature signal which is also fed to the electronic circuit. The circuit energizes a viscosity-normalized liquid flow signal, which is compared to a set point signal to generate an error signal. A valve connected downstream of the high resistance liquid flow path to control the flow of liquid is driven by the error signal and thereby controls the flow of liquid.

Liquid flow controller

A vertical flow thermal mass flow sensor for a vertical flow thermal mass flow meter of a vertical flow thermal mass flow controller has a sensor tube having a gas inlet for receiving a gas to be metered. The sensor tube includes a first curved convection trap and a second curved convection trap for preventing convective flow of the gas through the sensor tube. A thermally responsive winding is wound about the sensor tube and is energized from a source of electrical energy. The resistance of the thermally responsive winding is responsive to the rate of flow of the gas through the sensor tube and provides an indication thereof.

Thermal mass flow sensor

Gas flow control apparatus for controlling the flow of a process gas through a conduit system to a process site, for halting the flow of gas when the process is completed, and for then developing a partial vacuum in the conduit system sufficiently high to reduce the concentration of process gas and maintain it in a gaseous state. The partial vacuum is developed by carrier gas flowing through a venturi in communication with the conduit system supplying the process gas. The carrier gas also expels any remnants of the process gas from all points between the venturi and the process site. Further, the system can be used for vaporizing gases from liquids for use in an atmospheric process at the process site, the carrier gas flowing through the venturi and vaporizing a liquid in a chamber upstream of the venturi. The vaporized gases can then be regulated by a mass flow controller.

Gas flow control apparatus

A fluid flow stabilizer which includes two pluralities of stabilizer units adjacent one another. Each unit includes a plurality of parallel axially extending tubules. The units are movable into different relative positions so that certain of the tubules of a unit are aligned in fluid communication with tubules of another unit. Index means are provided for fixing the units in different selected relative positions.

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Orange, CA, United States of America

Randall J Vavra