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. 12, 1989
Filed:
Feb. 21, 1989
John B Duquette, Concord, NH (US);
Crathern Engineering Co., Inc., Contoocook, NH (US);
Abstract
A system for controlling the consistency of a material pumped from a reservoir, by introducing an alterant into the material, which system includes a diaphragm-type pump for pumping the material from a reservoir, the pump being driven by a double-acting air cylinder motor controlled by a pilot-operated two-position, four-way air valve having reducing valves connected at its air input ports to create pressure differentials between the input air and the operating air in the cylinder during steady state-operation of the pump. The motor is mounted so as to be relatively movable substantially toward and away from the pump responsively to change in the pressure differentials in the cylinder due to changes in the consistency. A compression spring, forming part of the mounting, is disposed so that under steady state conditions of consistency of material being pumped, an equilibrium exists between the forces acting between the motor and the pump, and the force acting on the motor by the spring, and the motor and pump do not move relatively to one another. A change in the consistency of the material will disturb that equilibrium, causing the motor to move relatively to the pump, and such movement serves to operate a valve that controls the introduction of alterant into the material.