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:
Aug. 30, 1988
Filed:
Sep. 16, 1987
Derek J Smith, Sutton Coldfield, GB;
Massey-Ferguson Services N.V., Curacao, AN;
Abstract
An hydraulic unloading valve for unloading hydraulic fluid from a circuit pressurized by a diesel engine powered pump under cold climate conditions to assist starting of the engine. The valve has an inlet through which fluid enters the valve, an outlet through which fluid may leave the valve, an outlet valve seat, a valve member movable towards and away from the valve seat and carrying a valve surface for closing off the seat valve, a first orifice sensitive to viscosity which in response to the flow of fluid through the inlet generates a first pressure drop arranged to tend to move the valve member away from the valve seat, and second orifice which is not sensitive to viscosity and which in response to said flow generates a second pressure drop arranged to tend to move the valve towards the valve seat to bring the valve seat and surface into contact to close-off through the valve outlet when the second pressure drop is greater than the first pressure drop. The pressure drop characteristics of the two orifices can be arranged so that at lower fluid temperatures of say below -10 degrees C. the valve is held open up to higher fluid flow rates, thus relieving load on the engine and assisting cold starting.