Peter Juodikis

US Patent:

39462005, Mar 23, 1976

Filed:

Feb 24, 1975

Appl. No.:

5/552761

Inventors:

Peter Juodikis - Chicago IL

Assignee:

GCA Corporation - Bedford MA

International Classification:

H05B 102

US Classification:

219499

Abstract:

A temperature controller for use with an electrical heater for precisely maintaining the temperature within a system at a selected set point, and employing an improved bridge circuit. A temperature sensitive resistor forms one of the two variable arms of the bridge circuit. The resistor varies in value as a function of temperature exhibiting a temperature coefficient of resistance which is not constant but which varies, decreasing with increasing temperature. The other variable arm, the setting arm, is in the form of a network, including a linear setting resistor and a pair of fixed resistors arranged in a series-shunt circuit. The setting resistor is linearly calibrated in terms of temperature, the series-shunt arrangement providing a composite resistance-set point temperature characteristic which closely corresponds to that of the sensing arm. The temperature controller further includes an operational amplifier which provides an output signal dependent upon the degree of bridge imbalance and a zero voltage switch responsive to the operational amplifier for providing trigger pulses to a triac coupled in the load circuit of the heater. A ramp generator is preferably included as a supplemental input to the zero voltage switch thereby to produce a control system in which the heat released is proportional to the degree the bridge is unbalanced.

US Patent:

45286353, Jul 9, 1985

Filed:

Jun 7, 1982

Appl. No.:

6/386044

Inventors:

Peter Juodikis - Chicago IL
Steven J. Martinich - Wheaton IL

Assignee:

GCA Corporation - Bedford MA

International Classification:

B01D 342

US Classification:

364501

Abstract:

A microprocessor controlled distillation analyzer for petroleum products performs, computes, displays and records distillation data. An interactive/keyboard display and printer system reports and records test conditions and prompts user inputs to define test parameters. Before the initial boiling point, the heater is automatically controlled in two time intervals. Following the initial boiling point, the heater is controlled to keep the monitored distillation rate within a predetermined range. Upon attaining an automatically calculated volume of distillate, the final heat is incremented to a programmed level. In one mode, the end point is automatically detected by monitoring vapor temperature for a decline, followed by the cessation of meniscus movement to terminate the test. After measuring the residue, the analyzer automatically recomputes temperatures at a series of percentage volumes of evaporated sample. An IR beam meniscus detector is driven by a stepping motor screw-drive mechanism actuated via the microcomputer to find the initial meniscus position and track the rising meniscus.

US Patent:

50000357, Mar 19, 1991

Filed:

Mar 9, 1990

Appl. No.:

7/491050

Inventors:

Peter Juodikis - Chicago IL
Clifford C. Johnson - Arlington Heights IL
Theodore Christie - Evanston IL

Assignee:

Precision Scientific, Inc. - Chicago IL

International Classification:

G01N 714

US Classification:

73 64200

Abstract:

Apparatus for measuring the vapor pressure of a volatile liquid includes one or more cylindrical test chambers immersed in a constant temperature water bath. Each test chamber includes connected liquid and vapor compartments, with the vapor compartment coupled to a pressure transducer and display arrangement. The test chambers are mounted to a movable tray in the constant temperature water bath. An eccentric drive assembly driven by the combination of a motor and gear box is coupled to the tray for linearly displacing the tray and test chambers in a reciprocating manner until a constant pressure is observed on the pressure display.

US Patent:

39462528, Mar 23, 1976

Filed:

Sep 23, 1974

Appl. No.:

5/508538

Inventors:

Peter Juodikis - Chicago IL

Assignee:

GCA Corporation - Bedford MA

International Classification:

H03K 1772

US Classification:

307252B

Abstract:

In the power controller disclosed herein, a load is energized from an a. c. line through a triac. When the triac is triggered on an a. c. half-cycle of one polarity, a capacitor is charged while the load is energized. The capacitor is interconnected with the gate circuit of the triac through an SCR and the charging circuit for the capacitor is arranged so as to trigger the SCR on the a. c. half-cycle following a half-cycle during which the capacitor was charged. Thus, the triac is selectively triggered on alternating half-cycles and integral cycle energization of the load is obtained.