The Foxboro Company

Thermedics Inc.

James B McGown

Edward E Bromberg

Lynn W Noble

David H Fine

Ernest F Root

Michel D Arney

Peter F McCrea

A Lindsay Carroll, Jr

Air sampling gun for collection of vapors

Disclosed is a portable, hand-held vapor sampling probe for collecting vapors of compounds such as cocaine, heroin, and explosives prior to their desorption and analysis in a vapor detector. Rechargable batteries power a lamp in the front face of the probe for heating target portions of a sampling surface, a puffer assembly for directing air jets at the target, and a motor for drawing air samples through a collector coil on whose surfaces vapors are trapped. A flexible U-shaped shroud on the front face partially encloses the lamp and collector and helps to regulate air flow over the target and to protect the probe from damage. Upon contact with a surface, the shroud may activate a switch which, together with a second switch on the probe handle and a lamp pyrometer, regulates heating of the target.

Vapor sampling probe

A float is disclosed for use in tank gauging systems of the type having a vertically supported guide. The float includes a donut-shaped body member adapted to be positioned about the guide to ride freely with the liquid surface. A discharged tube is positioned concentrically with the body member by a number of support members. The discharge tube is positioned below the liquid surface and acts as a discharge electrode to maintain the path of least resistance for an electrostatic discharge of the float below the liquid surface.

Float for use in tank gauging systems

An ultrasonic level measuring system is disclosed for determining by a time-ratioing technique the level of a liquid within a storage tank. An instrument sensor assembly, including a waveguide formed of a tensioned, ferromagnetic wire having a low thermoelastic coefficient is vertically supported within a storage tank containing a liquid. The waveguide is positioned to span both the tank liquid and vapor spaces. Two permanent magnets are positioned in close proximity to the waveguide at a known dimensional separation which defines the calibration span of the system. The waveguide and magnets are housed in a protective shield which acts as a process barrier and which is convoluted over a substantial portion of its length allowing the instrument sensor assembly to be easily transported and installed. A float, housing a permanent magnet, is positioned concentrically about the instrument sensor assembly to rise and fall with the liquid level. An ultrasonic transducer is formed of a field coil wrapped about a section of permanently magnetized, magnetostrictive wire. The magnetostrictive wire is butt welded to the top end of the waveguide. The field coil is excited by a current pulse introducing a torsional ultrasonic pulse into the waveguide. As the ultrasonic pulse passes each of the three magnets (i.e., the top, float and bottom magnets), a low level voltage pulse is generated across the waveguide. The voltage pulses are detected and amplified by sensing circuitry and coupled to a signal processing unit. The processing unit produces an output signal indicative of the liquid level by ratioing the time interval between the float and bottom magnets to the time interval between the top and bottom magnets. The resulting ratio is scaled by being multiplied by the known distance between the top and bottom magnets, (i.e., the calibration span) to produce a measure of the liquid level in the tank.

Method and apparatus for determining liquid level

Growing community of inventors

Attleboro, MA, United States of America

James B McGown