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:
Feb. 26, 1985
Filed:
Jun. 07, 1982
Kenneth E Lehrke, Maple Grove, MN (US);
Graco Inc., Minneapolis, MN (US);
Abstract
A fluid heater, particularly for heating paints, lacquers, varnishes and other spray coating material, includes an elongated hollow tube adapted to be inserted into a fluid flow line for fluid flow through the tube. An electric resistance heater is disposed within the tube and is surrounded by a helical coil member to create a helical fluid flow path through the tube. A temperature control system for regulating the operation of the heater is provided and includes a temperature sensing probe comprising a temperature responsive resistance element enclosed in a conical housing extending into the helical fluid flow path and having its apex contacting the heater and its conical surface area increasing in a direction away from the heater and extending across the cross section of the fluid flow path. The temperature control system is responsive to both the temperature and the rate of change of temperature of the probe and includes an ambient temperature compensation circuit for monitoring the ambient temperature and compensating temperature control circuits for regulating heater temperature as a function of ambient temperature as well as a function of static and dynamic fluid flow conditions in the helical flow path sensed by the probe.