The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 28, 1993
Filed:
Feb. 26, 1992
John A Benevelli, Burbank, IL (US);
Lab-Line Instruments, Inc., Melrose Park, IL (US);
Abstract
A temperature-controlled environmental chamber includes a resistance heater powered through a first solid state relay and a refrigeration unit including an electrically powered thermally controlled suction throttling valve connected in the refrigerant line between the evaporator and the inlet of the compressor, and including a bimetal motor and a heating element therefor powered through a second solid state relay. A thermostat senses the temperature in the chamber and compares it to a set point temperature and outputs a pulse-width modulated control signal indicative of the difference between the two temperatures. The control signal directly controls the heater relay for substantially continuous variation of the heater between minimum and maximum heating conditions. The control signal also directly controls the throttling valve relay by controlling the power to its heating element for substantially continuous variation of the valve between maximum and minimum cooling conditions, so that the amount of cooling provided is inversely proportional to the amount of heating provided.