Tylan Corporation

Innovus

Other

Dan B LeMay

Wayne Glenn Renken

Robert W Bosley

Samson Kirshman

Ricardo M Takahashi

A modulating valve is described for controlling the flow of a working fluid through a flow orifice. The valve includes a encapsulated armature having a permanent magnet and a pair of soft iron pole pieces within its interior. The armature is axially movable by the passage of current through one or a dual pair of solenoid coils surrounding the armature. A thin webbed sealing disk is stretched over the end of an armature housing extension and acts to close or modulate flow of working fluid by varying the axial clearance between the disk and a stationary annular seat of the flow orifice. The armature is supported on flexure guide springs that allow armature axial motion when axial magnetic forces are applied to the armature. These axial forces are provided by the interaction of the solenoid coil(s) and the field of the permanent magnet. A magnetic field gradient produced by the permanent magnet allows the coil to apply a force to the armature in either the valve opening or valve closing direction, depending on the coil current polarity. An armature velocity signal is used in a closed loop servo control of valve position to suppress valve oscillation and over shoot when a change in valve position is commanded.

Electromagnetic valve with permanent magnet armature

A mass flowmeter and controller measures the mass flow rate of liquid or gaseous fluids and controls the flow rate of the fluids being utilized in a processing operation. A series of flow channels and blocked channels are micro-etched from a silicon substrate leaving an integral membrane suspended across the channels. A heater-sensor thin film resistor, diode or transistor is formed on the membranes and the substrate during manufacture to sense the temperature at particular locations. A cover housing matching channels and grooves forms flow and stagnant blocked conduits in the structure. Through a bridge circuit a signal indicative of mass flow is produced. This signal is passed to a control valve armature coil in an in-line flow control valve. The controller includes a sensor module containing monitored flow and blocked channels and passive by-pass channels as required for additional flow capacity, a control valve cartridge, an overall housing and the magnetic armature coil which controls the flow of fluid through the valve and the sensor module.

Thermal mass flowmeter and controller

The flow meter (10), particularly useful in monitoring flow in semiconductor manufacturing operations, measures mass flow rate of fluids and is fabricated by providing spaced webs (16) deposited on a silicon substrate (11) and fluid flow grooves (13) etched across a substrate surface and extending under the spaced webs. The webs 16 include a low thermal conductivity layer deposited in spaced aligned portions of the substrate and electrically resistive pathways deposited on the layer portions (61). The webs act as temperature sensors and/or heaters. Heat is added to the flowing fluid and a differential temperature is measured on a bridge circuit as is known in the art to measure flow rate. A cover (12) has etched grooves (14a) which match the grooves (13) of the substrate to form a fluid passageway in which the web bisects the passageway forming an 'air-foil' like bridging member extending completely across (or cantilevered across) in transverse relation to the flat sides of the substrate on either side of the groove. Normally multiple series of webs and multiple grooves are employed to provide redundancy of the flow meter channels in the event contaminants plug a particular channel.

Thermal mass flow meter

The invention is a system for controlling the mass flow rates of vapor and carrier gas in a flowing fluid mixture. A regulated flow of carrier gas is divided so that a fraction of the flow passes through a vaporizer to pick up the vapor while the balance bypasses the vaporizer. The streams are then recombined and the resulting mixture is passed through a dew point detector which gives an output signal which varies according to variations in the mass ratio of the vapor to the carrier gas. A controller responds to the detector signal to generate a control signal which modulates a valve to vary the fraction of the carrier gas passing through the vaporizer, thereby influencing the mass rate at which the vapor is introduced. The feedback control from the dew point detector to the valve is adapted to regulate the dew point, and thereby the mass ratio of vapor to carrier. Since carrier mass flow rate is separately regulated, the regulation of the mass fraction of vapor in the blend results in the regulation of vapor mass flow rate as well.

Vapor feed regulator

A mass flow sensor system for measuring the flow rate of a fluid in a sensing tube at diverse angular attitudes. Output signal distortion is minimized by neutralizing the effects of convection forces. The sensing tube is formed as a by-pass coupled to a fluid conduit and includes a loop in the shape of a single-turn helix. Circulation of the fluid through the loop cancels gravity-induced convection forces caused by temperature gradients and significantly reduces sensitivity to attitude change. Heating and temperature-sensing resistor coils are wound around the outer surface of the looped portion of the tube. The heater increases the tube temperature above that of the entering fluid, and the temperature difference between the temperature sensors, corresponding to rate of mass flow, is detected as a voltage output signal generated in an associated bridge circuit.

Mass flow sensing system

A mass flow sensor system for measuring the flow rate of a fluid in a sensing tube at diverse angular attitudes. Output signal distortion is minimized by neutralizing the effects of convection forces. The sensing tube is formed as a by-pass coupled to a fluid conduit and includes a loop in the shape of a single-turn helix. Circulation of the fluid through the loop cancels gravity-induced convection forces caused by temperature gradients and significantly reduces sensitivity to attitude change. A center-tapped temperature-sensitive resistor coil is wound around the outer surface of the loop. The coil is heated, and the temperature differential between the ends of the coil, corresponding to rate of mass flow, is detected as a voltage output signal generated in an associated bridge circuit.

Mass flow sensor system

Apparatus and method for obtaining a controlled gas mixture of predetermined proportionality using a temperature dependent permeation tube or like source for the addition of a small amount of a constituent gas in a higher flow rate carrier gas. A thermistor having a negative coefficient of resistance is associated with the permeation source and electrically connected to a flow controller for the carrier gas to automatically regulate the flow rate of the carrier gas in accordance with temperature variation of the permeation source.

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Palos Verdes Estates, CA, United States of America

Dan B LeMay